For the remaining two slots, either two more chanters, or a cipher or two.
Max perception (for accuracy bonuses) to the ciphers and yourself.
Everyone else DUMPS perception and dexterity to as low as it can go.
Put their perception and dexterity points into CON, MIGHT, INT. Max them out and keep RES at 10 -12.
Get the "Summon Ghost Spell" for your chanters.
Set AI to "Summoner" and "Defensive."
Works on POTD. Very very effectively with minimal work. Most of the time I just let the AI do the stuff
The strategy is to use your ciphers to mind control and CC the enemy to make the encounter last longer.
And let your chanters build up chants to summon the ghosts.
At which point the ghosts kill everything.
Killed Raedric at lvl 3-4 with this party on FIRST try.
Killed Temple of Woedica on level 4-5 on FIRST try.
Killed the stupid fight in that small room with the stunlocking banshee and 4 Justicars on... 10 tries. But I did it with a lvl 4-5 party. And I'm a noob (first time playing this game, though I finished Deadfire).
This is the ultimate noob friendly party. Very little positioning required. Run into a room, let the ciphers CC a few enemies to buy time for the chanters, summon the ghosts, kill a bunch of enemies, rinse and repeat.