Unless there’s literally huge hairballs in the water, or your rabbits seem susceptible to fur blockages, I think a few strands in the bowl is fine, especially since you’re changing it regularly.
Hand grooming is fine, as long as you’re getting an effective amount. I only hand groom Wick because brushes don’t take anything off, while one clasp of my fingers on his butt takes off a lot of fur. Also with hand grooming, you learn about your rabbit’s molting pattern and how it sheds, allowing you to do it more effectively. Wick has his distinct molt lines, so I tug against that daily to see where new fur has grown in, ousting the old fur. Also, you can easily tug-check tufts that look loose that aren’t on the molt lines, and tug the surrounding area to find a gold mine of loose fur. I honestly think it’s the most effective method if your rabbit tolerates it, and you’re willing to learn as you go to be the most effective grooming hands.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.