Jones sees the most play in general right now so that seems like the best option but as you mentioned the Rogue nerf might make it played less. But at the same time, if people run less weapon hate then warriors will start using super collider again (I already play one in bomb warrior and it's a life saver against miracle mage), so hitting that with a harrison on curve would be a big deal.
As I browse over the top legend miracle mage decks over the last two weeks are so, I see all three of these cards being run and not run. So really none of them are core but all are good. If you really love this deck, i'd say get Antonidas or Luna. You seem to want Luna which is a solid choice but were this deck to be nerfed or something, that would probably be the least useful card going forward, but that is hypothetical and might not even be true.
Antonidas is mainly good for finishing off slower decks, especially warrior. Luna gives you a turn 3 play when you often won't have one and sometimes lets you go ham with draws, and Jones just feels good when it hits an important thing. I'd just craft whichever you think would be the most fun to play. Though you could also consider what other deck(s) you might want to pick up eventually that run one of these cards.
I think both Antonidas and Harrison are safe crafts. First one is class limited while second is neutral, but they always see some play. Also they both are classic cards so they won’t rotate out and you will get dust back if they ever get to hall of fame.