You're making your characters do way too much, they are all hybrids and you're over-complicating them. This also isnt a real pure magic party.

Some points
- You only need 14 STR to do quest checks. You also only need 14 STR for STR armor if you want survivability.
- You dont need CON on your other characters at all. That being said you can take it if you want, but in moderation. Armor is more important than HP.
- Never take weapon skills. Skills are multiplicative, weapon skills are not. i.e. A point in Warfare grants you a bigger damage boost than 2Hander.
- Do not take warfare on your magic party
- Do not spread out skill points across four magic trees for your DPS
- No summoning. Period. Its an easy crutch. If you do take it then the character should be 10 Summoning/2 Necro for Summons and Bone Widow and he should only focus on that.
- No Wits, it does not help with who goes first since this initiation system is a mess. Unless you know what you're doing for a crit build.
- You do not need any physical damage at all.
- You only need 1 support character, and they should have Geo/Hydro.
- Taking 2hander is a waste. You wont be melee attacking, and it will only give more damage to spells on characters who primary weapon is scaling into their ability as well. In other words its just an over-complication, likely going to be over sighted and leading to massive DPS drops.
- Do not take glass cannon. Your character will be focused, CCed and die. The minor AP boost is not worth it. Glass cannon is something that should only be on a character who cant get targeted like Scoundrels.
- Comeback kid is begging for failure. A talent that helps you deal more damage or survive while you're alive (like Living Armor) is more valuable than one that only works when you die, and just postpones inevitability. You shouldn't be letting characters get that low in the first place.
- Living Armor on everyone
- No Opportunist on your magic pure party
- No Morning Person
- Savage on every DPS
- Far Out on everyone

The fact is if you want to be efficient your party will look like this

1. CON only, exception for memory. Geo/Hydro maxed. Entirely a buffer/debuffer/CC remover. Can take Pyro/Aero/Necro for 1/2 points for other buffs. Shield. Does not deal damage.
2. Three DPS characters. INT only, exception for memory. Each with Poly Invis, and Scoundrel/Huntsman escapes. Best combos are;
Pyro/Aero; works because both are high DPS, with lots of AoE on self skills. You may want 14 STR here for STR armor since they are in the thick of the fight.
Pyro/Geo; Poison and Fire, obviously work together.
Aero/Hydro; Water and Lightning, obviously work together
Geo/Pyro; Poison and Fire again, but focused on poison/earth more-so than fire.

You should get to 10 on the main skill first, with 2 points on the secondary so they are still viable for fighting element immune enemies. Assuming you max out both skills (which you probably wont) then Huntsman is next best thing for more damage. You will already be spreading yourself thin by putting points into Poly/Scoundrel/Huntsman for utility abilities, which you should do.

Thats literally it. The above will let you breeze through the game and never face a single challenge. The problem with Divinity 2 is it lacks depth, and once you know the mechanics simplicity is king. Taking something that's hybrid can work, it can be fun, but it isnt good in comparison to a focused character. Your support can keep everyone alive, and deal with all debuffs. Your DPS will be dealing so much damage that the enemy will be dead before they can get into a long fight. And the shorter the fight the easier it is for you.