I wouldn't worry about Cha really at all. The only things it affects are your Consume powers and your blasting exploits- none of which are worth it, by the way. If you do find yourself constantly running out of arcane reservoir points, just grab the Fiendish Proboscis exploit- it's... not well-balanced, let's put it that way.
I would always go school. The extra spell each level prepared is incredibly useful for an arcanist on top of the school abilities, well worth 3 exploits.
I agree with dumping Charisma,you still have the option of burning a spell slot with a negative charisma modifier.
A positive charisma modifier is only really useful for the Occultist archetype who in their case are burning spell slots to turn points into summon monster spells.
On Daedalus recommendation of fiendish proboscis only even humor the idea if you play at a very high powered table. It's a very poorly designed game breaking exploit.
I am constantly surprised by the number of people who say Charisma is dumpable on an Arcanist - rather than spending points on blast exploits you should be spending them to boost individual spells by +2 DC or CL with Potent Magic. That comes in handy constantly, and coupled with Quick Study you'll want to have as many points as possible throughout the day. It isn't that hard to put something into your Cha score - 8-14-12-16-10-14 pre-racial stats works just fine for starters, and a good headband split between Int and Cha will ensure you have plenty uses of Consume Spells / Consume Magic Items to refill your points. I GM'd for a guy who went this route and absolutely dominated the campaign.
I am constantly surprised by the number of people who say Charisma is dumpable on an Arcanist - rather than spending points on blast exploits you should be spending them to boost individual spells by +2 DC or CL with Potent Magic. That comes in handy constantly, and coupled with Quick Study you'll want to have as many points as possible throughout the day. It isn't that hard to put something into your Cha score - 8-14-12-16-10-14 pre-racial stats works just fine for starters, and a good headband split between Int and Cha will ensure you have plenty uses of Consume Spells / Consume Magic Items to refill your points. I GM'd for a guy who went this route and absolutely dominated the campaign.
A well played full caster will dominate any table. We advocate low cha because a higher int is more valuable. Increasing cha has a minor effect on point total(only increasing consume) meanwhile int gives additional spellslots(the biggest weakness of the class). There is only 1 or 2 good exploits that work off cha meanwhile every spell you cast scales off int. I've played it both ways and int solo is much stronger. In that array drop the cha to 8 and you have 18 int. That at the very least is 1 spellslot and +1dc to ALL spells. Compare that to being able to use consume 1 more time per day
@OP fun concept. Probably will use as an npc at some point. I like vanilla better than school but that really is a personal preference. Wouldn't do it for any of your given schools though. You can already grab dimension slide and extradimension school is fun but fairly limited. Enhancement school would be my pick of the 3.