Ok, so the write-up starting with stats (fully buffed) and equipment with some strategy.
All characters are level 52.
Kincaid: HP 1385/SP 488, 16 dex, 16 con, 9 will, 20 blades, 10 thrown, 14 lore, 9 leadership, Darting Steel 8, Storm of Steel 1, Sure Parry 8, Flanking Unity 8, Live by the Blade 1
armor 149, 49 strong dodge, 30 extra parry, elemental res 44, unholy 6
Main hand, Flambard 63-148 at 3 ap and 10 acc and 9 parry, off-hand, flash knives 1 ap at 37-68 with 10 acc
Charger Studded Leather: 114 armor, 3 evasion, 1 move point, 325 hp, 6% critical, 8% drain
Wise blood ring: 10% critical, 5 dodge/5 parry, 10 stealth, 10 security
Cloak of Names: 12 elemental damage, 12 dodge, 12 resistance
Ironsoul Boots: 8 parry/8 dodge, 12 resistance, 4% drain
Kjartan: 1052 HP/1540 SP, 16 con, 14 knowl, 10 int, 11 polearms, 20 sorcery, 9 conjuring, 5 immolation, 10 choking ash, 2 meteoric shockwave, 10 pure flame shield, 9 burning blades
Armor 96, 10 dodge, 6 parry
Main hand: staff of nahama 40 hp, 280 sp, 4 acc, 12 dam
Robes of the Fourth: 60 armor, 3 evasion, 1 move point, 88 sp, 3 ranged acc, 2% crit
Gauntlets of Song: 160 hp, 160 sp, 8% drain
Webbed Cloak: 180 hp/180 sp, 2% crit, 8% drain
Snake scale Boots: 1 move point, 4 ranged acc, 8 dam, 2% crit, 8 armor
Kyera: 1178 hp/ 1008 sp, 16 str, 16 con, 7 int, 8 knowledge, 20 hammers, 18 invocation, 9 conj, 6 lore, Banishment 10, Ethereal Anguish 10, 1 Sacrifice, Myshana's Tears 2, Purifying Breeze 1, Warder's Shield 10, Piety Ward 1, 1 extra talent
Armor 124, extra 14 dodge, extra 14 parry
Main hand: Keen Warhammer, 71-102 dam, 7 acc/5 parry
Off: Braeysguard, 9 parry, 120 hp, 3 melee acc, 12 dam, 2% crit
Edict Plate: 96 armor, -2 stealth, 150 hp/ 150 sp, 4 parry
Long claw Boots: 1 move, 4 parry/ 4 dodge, 4% drain
Pendant of Scrying: 260 sp, 4% crit, 12% drain
Right Fist of the Barbarian: 6 acc, 24 dam
Selen: 1064 HP/ 459 SP, 9 blades, 20 bows, 4 lore, 20 stealth, 8 Punishing Blades, 8 Pinning Shot, Sly Look 4, Dance of Shadows 10, Quicksilver 5
Armor 72 armor, 15 parry/ 18 dodge
Main: Keen Tulwar, 7 acc/ 8 parry, 36 - 51 dam
Off: Iceheart Bow 43 - 116 dam, 7 range, 13 acc, 24 ice dam, 5% crit
Novir Leathers: 44 armor, 8% drain
Hellfire Cloak: 24 fire dam, 4% crit, 4% drain
Ring of Danka: 16 dam, 7% crit
Torc of Dread: 3 acc, 24 dam
Kincaid's role: Avoid attacks at most any cost. Wasted enemy attacks cost 0 SP/potions to heal and 0 AP. Early game by Red Hill, Sure Parry to 8, CF as you can, 1 live by the for utility in early game, 1 FU for utility. Emphasize plus parry and dodge. With reasonable equipment drops, I usually can plop Kincaid down next to ranged enemies to guarantee attacks to him and not to the party. Use 1 AP/ 2 AP Blade combo for great damage and best stats. Red Hill or shortly after 1 Storm of Steel for area damage. Middle game, max CF for parry/dodge, crit, and acc. Add FU later up to 8 for acc/dam. Saved talents for Darting Steel. Raise slowly rest of the game to balance SP usage and drain. For most of the game, 1 AP/2 AP blades work very well for delivering damage. 1 SoS give area damage for much of the game. Late game. Raise Darting Steel to provide 1 AP area damage and extra minus parry/dodge. Raise to 9 eventually for 4x4 area with appropriate damage, crits, and drain to be self-sufficient for mass area damage. While lower damage, using Kjartan and Selen lowers armor such that low damage weapons with crit does massive damage.
Kjartan's role: Curser with damage added later. Early game by Red Hill Keep CA to 7 for keeping armor to 0 and hitting enemies. 2 Meteoric Shockwave for -4 acc and aiding avoidance attacks. This is very much key as as -4 acc allows Kyera to be a secondary tank for much of the early game, and helps ensure Kincaid's safety from accurate enemies. BB and PS added in at low levels. PS is a passive boost to survivability. Very useful in the Underforge for later game. Raising this is adding effective HP to the party by reducing incoming damage. The resists are useful to negate enemies that do +all damage. Mid game. Max CA. Raise PS and BB in a 1/2 fashion until advanced. By Ep 3, add three points to Immolation to give Kjartan some punch and added crit chance for the party. Late game. Finish maxing PS and raise Immo and BB to improve damage. Kjartan is a curser and defuffer most of the game. This maximizes the capacity of the other three characters to their best. Fireball 1 does a decent amount of damage to finish stragglers if you maximize equipment accordingly. Later game, immolation starts to take off as a damage dealer plus boosting party damage. Equipment that bolsters HP and SP is great as well as equipment that bolsters damage, acc, and especially movement to give Kjartan the greatest utility of curses and attacks.
Kyera's role: Holy warrior with hammers and SP drain to fuel the party's damage and decrease camping for score improvement coupled with EA to take away panic of assaulting enemies. Early game. Hammers all the way to increase parry ability. Max Con for survivability. Raise Myshana's tears to 2, focus on Warder's Shield for avoiding party damage. Above all, Kyera is used as a secondary tank at the Bridge and other pincers. WS, high hammers, a shield, and equipment that focuses on parry/dodge are utilities to survive pincers comfortably. Meteoric Shockwave is immensely useful for aiding Kyera. Absolutely use EA to reduce damage. Add 1 to Sacrifice. If you load Kyera up on % drain gear, she can often drain enough to supplement the other party members. Add 1 PW for managing the Baron if you do take damage. At lvl 1, EA is hugely useful to drop incoming damage to a manageable level as needed. Mid game. Finish maxing WS. Start developing Banishment. Not useful right now but will be so in CoD and Ep 3 to provide a ranged choice for Kyera. Raise to 7 for area of effect. After, raise EA to 6 for -2 AP. Being able to drop necromancers to 1 AP is a must! Then eventually max. Late game. Finish maxing Banishment. After that, I don't know, extra talent points to your desire.
Selen role: Stealth lead all game followed by ranged damage extraordinaire. Early game. Raise Pinning Shot to 5 and then focus on Dance of Shadows all the way to 10, maybe a point in Quicksilver Defense for safety during a failed stealth roll. Emphasize Stealth, usually having stealth armor and always try to raise stealth 1 pt per level whether through item, talent, or skill. Winning the first round ensures one can scout where enemies are and choose defensive territory to maximize survival. After that, PS is a cheap and effective way to increase hitting ability, do area damage, and most importantly strip 1 AP from groups of enemies. Between EA and PS, nearly all enemies will only have 1 AP. Secondly, stack acc/damage items on Selen, adding in Crit % and Drain % as feasible. In maxing damage options, Selen can effectively clear mobs of low armor enemies much of the game when you need to drop damage quick. As Selen only has a regular bow attach, acc is very important to her such that her regular attack is effective. Mid to late game. Improve scout talent to 4 for max area coverage and extra range. Continue the above strategy. Once Dance of Shadows is maxed, I started on a combination of Punishing Blades and QsD to my taste. PB will be maxed, and a modest level QsD allows a good chance to avoid the stray hit or two.
Overall battle strategy. Scout everything you can. Always identify where ranged damage is coming from and make a choice if Kincaid will tank it or move out of range to draw attackers out. Curse as needed for offense and defense. EA is your greatest asset for neutralizing enemies that can't be killed quickly and need to be made toothless. My absolute favorite talent in the game. EA 10 at 2 AP lets you blanket a field if needed and lowers acc by 7 to boot. Kjartan curses for offense reasons. CA is great for increasing consistent offensive output. I despise missing attacks. CA with PS with FU and late game DS pretty much means I never miss unless against very high defense enemies. Orcin warlords. Late game trolls and wolves (the level 60 stone trolls on the way to Freeport were a pain). Missed attacks are wasted AP and lowers damage output. Selen is my main damage dealer much of the game followed by Kincaid. CF allows him to tank but be reasonable in offense. 3 AP attacks hit heavy with SoS and help with high armor enemies. Kyera has great selective damage through her hammer swings. Usually focused on one enemy, I use her to take out the nearest enemy threatening us, allowing Kincaid to push the line of assault forward. With Kincaid being a major tank, the other three party members can shift around as needed on the battle scene. Late game strategies give more options, like when Kyera has Banishment as a choice, but by then you should be able to choose an optimum approach that balances offense (major SP usage of all talents) versus moderation that supports SP drain to kick in, extending time between camping.