Those two conditions are big and if they're not both the case, then I doubt we'll see this happen. However if they really are still largely outside of White Hat control, and if RFK Jr. isn't just a gullible moron and actually understood and believed in the globalist agenda, I can't see them taking ANY other path but to use him.
Imagine how many young people they could win back by having a big "people's revolt" at the convention, riling up what's left of that Bernie Sanders energy and getting a candidate people don't absolutely hate. They'll have their party insiders that voters hate whine about it while all the state delegates "revolt" against the party right on cue, and play that narrative to the media.

Now to be clear, I don't think this would be enough to beat Trump, I don't think anyone who has woken up about the left is going to go back across because of him, but they absolutely could get a lot of disaffected leftists back on team Dem. (Although his diehard Israel support will hurt him bad on that front). What I'm saying is they could turn this back into a race, and if they do, the doomers on our side will go into overdrive like we have never seen before. That is the biggest threat to this movement, fake "conservative influencers" whose sole purpose is to seed doubt when things are going well and despair when we have the slightest setback. We think they're one of us because they identify the real problems, but they hammer into our heads that the left is bigger, badder, and has way more support than it actually does. They acknowledge elections are rigged, and yet go into a doom spiral every time CNN or MSNBC releases a poll claiming the public is on their side.

So long as we manage not to take that sort of bait, push like we're losing even though we know we're winning, and party like it's 2016, we will be golden.