Can Evocators Cast Endless Spells?

Nope, only Empower and the Lore of Invigoration spells.

Can Evocators cast spells?

It cannot attempt to cast any spells other than Empower, but any number of units of Evocators can attempt to cast Empower in the same hero phase.

Can you recast an endless spell?

You cannot dispel an endless spell and cast it again in the same hero phase. ... Most spells went up in points to compensate for the double movement per round (each hero phase). All warscrolls have been rewritten (if in doubt, you can find them in the FAQ or in the General's Handbook 2021).