I don’t have a long haired bunny- but I thought I would mention to make sure you take a disinfectant to clean each used comb/brush between bunnies- as I think owners will appreciate any small bti of caution.

I am sure others will be able to offer grooming advice- but I have short haired bunnies and cats- for that very reason- mats. 

If Wooly gets a little mat, I just cut it out. His fur isn’t just long though, it has a wire texture to it. So if a mat does take hold, it is very difficult to undo it without cutting. He doesn’t seem to mind though. I think he would prefer that over having his hair pulled on.

Disinfectant wipes are faster, and easier. I would suggest getting a box of latex gloves too, that you can change out as needed to avoid spreading anything the bunnies may have to others. And have a large stack of towels too! One per bun, so you can gather fur on each towel to wrap up to avoid anything again.

Have a couple kinds of brushes handy, a slicker, a comb, and a nice rubber one that I will link as well. They are all awesome to work with, my fav is the rubber one I will show you. Have a small pair of scissors for mats, and a good sharp pair of clippers for nails. I like the scissor clippers myself

For mats, you will want to tug gently, work your fingers into the fur to try and pull it apart before resorting to cutting it. Often it is just stuck together and can be fixed with just some patience, no cutting. But have scissors for the stubborn ones.

http://www.petco.com/product/106332/KONG-Cat-Zoom-Groom-Brush.aspx