Doing a Vanilla run with a Re-Re is perfectly possible, but it’s harder because:

1) You can’t get a Pistachio streak as big as the other clbumes unless you spend a lot of money beforehand

2) You can’t speedrun a lot of forums, so Lemon potential is lower

3) You have to rely on low-level forums, which have a faster turnover, which is good and bad at the same time: while you spend less time running, you might get 2 forums dominated while you kill another one.

I’m talking from my solo experience, of course; I think a Re-Re raider would be even harder unless you can get some of the higher level forums as anchors.