@ Theurgist at the moment I took build advice from thelee.
Party is lvl 7 so I'm starting to see some fruits come from spells and skills. Most fights I pretty much start off with chill fog or slicken depending on foes. Tekehu also has chill fog thx to his background traits. I'm using Pallegina with the endless paths greatsword and she's doing pretty well besides eder. My mc bounces back and forth between Eldritch aim, blood sacrifice, chill frost or slicken, and cancolhaults corrosive siphion. Noxious burst as well. Once things are as best as I can cc them with my main I start using Eldritch aim and then escape to get behind someone my tanks are engaged with and try to get a stab or 2 in. If they start to agrro me I escape to safety and start siphion again or actually heal.
I am wondering if I should pop smoke veil the use escape to get behind a engaged enemy to get a sneak attack in. That's basically what I have been doing with the mc. My companions have custom behavior set for some of their off the rip skills and I try to micro manage anything that needs to be done in fighting.
There is alot I'm still learning but since I added tekehu and Pallegina to the group I have been able to take on more enemies. I am have a tad bit of trouble with the The Cornett's Call in the ancient city where my fights are really close usually one or 2 enemies are at a quarter health when I'm out of everything. Need to prep more potions or scrolls. I'm not using consumables as much as I should.
Interesting setup on your MC. Keep in mind that pulsing spells (Chill Fog, Slicken) will break your invisibility.