Well, I have seen many situations where rabbits got anlong with cats perfectly well, but I would suggest you to be careful, anyway. How well-behaved are the cats? Do they like being outdoors and maybe hunt for birds or mice? Especially if they're young and playful, they can (unintentionally or not) hurt the rabbit.
It also depends on what kind of rabbit you are planning on buying. Personally I love the really small races, but they are quite often shy or nervous, and take lots of gentleness and patience to tame. If you want it to be the petting-cuddling kind of bunny, I'd advice a larger, more 'slow' race. By slow I mean one of those kind of dull-wittedbeasts that allow themselves to be picked up at all times. I have a dwarf rabbit myself and NO WAY will it let me pick it up - me and my sister/mother are the only ones allowed to even pet it.
Also, did your friend tell you she would like a rabbit? Pets can be a lot of work, and I think you need to make sure she's willing to put in the effort.
Hope this helps
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