It sounds like things are going well, and that your friend has a very unusual pair of bunnies. Don’t be surprised if hers stop being in her lap soon. Your bunnies are behaving perfectly normal, and I’m happy to hear they are bonding well. When 2 bunnies have each other, the bonding to their human often takes longer and is more subtle, so don’t worry. It’s good to try to spend some alone play time with each of them separately sometime down the road, so you can eventually establish a relationship with each one. But no bunny is truly a lap bunny given a choice, so it’s nothing to despair over. Most bunnies don’t really like being picked up either. Mine never liked it, even when one let me do it more than others.
Nail trims are difficult, and if you want help for the first time, I would suggest a wellness visit to the vet you decide to use, to establish a record with your vet for each bunny. They make baseline notes, and you can request a nail trim. The vet can show you how as well, if you ask.
As far a grooming fur, I find that a brush or comb, like the Hairbuster, is gentle enough that the bunnies like them. I don’t try to put my bunny in my lap, just pet with my hand first and then bring out the comb and gently comb from head to back in the direction of the fur. You will get some of the fur off, and your bunnies will get used to you doing it for very brief periods. It may feel good to them, even if they walk away quickly. My new bunny Spike will stop eating while I run a comb along his back because it feels good, but only for a few seconds.
Sounds like they could be shedding, and are helping each other groom. If you are worried about ingested fur, just hand vac or sweep up the loose stuff, comb them anytime they are near without making a big ritual, and give them plenty of hay and water to digest it. I give Spike the digestive treats (Oxbow’s, in the BB store) to help keep digestion flowing so the fur doesn’t cause a blockage. Just wetting your hands and petting them can also transfer a lot of loose fur to you, that’s hard to wash off yourself!
It sounds like life with your new buns is going very well. 