A nest box with the fur and babies in it is the best place you could have moved them. Baby rabbits die for unexplained reasons, so don’t beat yourself up about it.
I’d leave mama alone in the cage until their eyes are open, let her do her thing and care for her babies. Petting and treats are fine, but I’d leave her alone other than that to take care of herself and her babies. Give her some alfalfa in her hay to help with her milk supply, and make sure she always has plenty of water and offer her unlimited pellet food as well.
I’d check the nest once in the morning for the next few days, see if their bellies are nice and round, if they are then mama is doing her job and you can leave them be. You might or might not see mama ever nurse the babies, rabbits only nurse once or twice a day.
Mama will probably wean them on her own (in my experience this happens 4-6 weeks depending on the mama) and at 8 weeks they can be separated into a baby-only cage and find their new homes.
By 2 or 3 weeks make sure to keep and eye on the cage, babies like to test out their legs and sometimes escape!
There is probably 2 or 3 sizes of kits in her litter. The larger kits were rabbits that didn’t inherit the dwarf gene from mom or dad, the slightly smaller ones have a single dwarf gene (these are the babies that have show potential). You said mom was big for a Holland so I’m assuming she doesn’t have a dwarf gene, but if she does, you might notice a TINY baby in the mix. This baby is called a “peanut.” They inherited two dwarf genes and rarely make it to adults. (There is hope though, sometimes a “peanut’ turns out to just be a small runt.)
I hope this helps!