It's perfectly okay for a bunny to feed her babies more than twice a day. I've had some mom's who I had to help feed by putting them on the nest and others who would feed their babies every couple of hours. All the babies grew up nice and healthy. The ones that where fed more frequently where a lot rounder but they all matured at about the same rate once they started weaning.
The babies will start to get fur at a couple days old and it will continue to grow. You might be able to see the startings of the fur if you take a look at the babies now.
Their eyes will open at about 10-14 days. You want to make sure that all their eyes are open by 14 days and if they are not they can get infected. If that happens, let us know and we'll help you.
When I have babies, I always start handling them very young. I take the babies out and snuggle with them on the couch in a fleece blanket from a few days old. I find the human contact helps them to be friendlier when they mature. You should at least check over each baby every day to make sure they are all doing well.
After their eyes open, they should start moving around more. Make sure the enclosures they are in don't have any places for a baby bunny to get their head stuck.
Good luck, and please keep asking questions! We are all here to help you.
--Dawn