After reading through all of this, definitely take Inspiring Leader. The only other character in your party who's definitely going to have a high Charisma score is the Warlock. Let him use his early ASI/Feat slots to max his Charisma or for something like Spell Sniper, Crossbow Expert, War Caster etc. to make his blasting more effective. Your starting scores are kinda nuts, you can afford to go with a feat right off the bat. And as a Paladin tank, taking something that boosts the survivability of your whole party is very much in character. Sure, it won't be quite as powerful at higher levels, but bonus hit points are still bonus hit points. Someone refresh my memory, temporary HP still count as yours for purposes of being required to make a Con save to maintain concentration, yes? They aren't like the HP of an Abjurer's Arcane Ward?