I think just health, mana, restoration and stamina potions show up in the shared potion bar. You can open your inventory to use other potions (don't know if you can assign hotkeys for them, but I'd think not).
You can assign hotkeys to activate non-passive skills, though the active skill icon is not always shown as it was in Divinity.
You need to lean party based healing skills. I believe the one available at the start is just individual healing (ie the spell caster).
You need to find a book or teacher to learn other skills first, then you will be able to put skill points into anything available. You original selections only effect your starting skills.
