If I buy these can the posts on back just be used for wire connections?
https://www.amazon.com/gp/aw/d/B072...=FHBAGKF3ZWBHR8T3BX0W&dpPl=1&dpID=71irqygRLAL
No. Those are gu10 adapters - and while technically yes, you could power each terminal directly, you’re just asking for an electrical fire or electrocution risk. Use cleated sockets, vanity strips, flush mount sockets, etc that are meant for this sort of thing.