Possibly mites, but if they have head tilt it's very likely they have ear infections. My one rabbit has had two ear infections, and once he got very bad head tilt because of it. I did my research so I know a fair bit about ear infections.
Ear infections can be pretty deadly if not treated...sometimes it's just a common virus, like pasturella, but other times it could be worse infections that can get to the brain and pretty much kill the rabbit.
These infections aren't caused by worms, either. I took mine to the vet so we could get meds to treat him, but I understand you said you can't do this. I'd keep asking around or do some research on how you could possibly treat at home. Looks like JCV's bunnies has some knowledge on how to treat!
Another thing to note, is that depending on each rabbit and how bad their infections are, they could potentially have head tilt forever (just a little to severe, depending) or lose some balance. Perhaps such young buns would bounce back quickly, but I don't know. My rabbit was like 9-10yo when he got his really bad ear infection; the head tilt went away but he's always had worse balance since then. Still gets around just fine and is happy, but I do notice it.
I hope you can find a treatment that works soon, and your little guys have a speedy recovery!
