Chariots aren't infantry, but neither are they a large target, construct, or vampiric unit. Thus they can be raised the full 1+wizard level off Invocation of Nehek, or D3+1 from the Restless Dead lore attribute for Lore of Nehekhara.
Ushabti are arcane constructs. Thus they are capped at 1 wound per spell (or 1 per magic phase if you're generic TK).
It's worth noting that Morghasts can be raised the full 1+wizard level, just like crypt horrors can be. Ushabti are kind of shit TBH.
EDIT: also note that raising back wounds onto a chariot unit means you get the extra impact hits for raised chariots. Pretty wicked. I actually quite like small units of chariots (3-4) as flanking and support units.