Your basic strategy should be to do it slowly and don’t go beyond the dog’s threshold. His threshold is the point where he’s so excited that you can’t make him pay attention to you again. So, start with the rabbits securely in a cage and the puppy securely on a leash. Bring the puppy in and stop while he’s calm and looking at the rabbits, then give him a treat (a clicker works well here if you’re using clicker training – I highly recommend it). When he can be calm at that distance (not tense, not whining, etc) you can move him a little closer. At each stage he needs to listen to you when you ask him to sit or lie down and he needs to be calm – if it’s so fixated that he won’t listen to anything you say, then move back a step. You might have to work on one distance for days or he might be able to get closer fairly soon (knowing boxers and labs I think it’s likely to take quite a while – both breeds are hyper as puppies and slow to grow up, so he’ll probably want nothing more than to play with the bunnies at first).
Just keep working on this slowly in 5min sessions (you can do a couple sessions per day) until he’s able to be near the cage and completely calm around the bunnies. At this point you can let him off the leash with the bunnies still in the cage. If you can get to this level I think you could trust that if he forced his way into the room while the bunnies were caged, he at least wouldn’t launch himself at the cage trying to get them out. The next step would be to let the bunnies out of the cage with the dog on the leash, but you might not want to go this far if you don’t plan on ever having them out together.
If your wild rabbit is really a cottontail, and not just a wild looking domestic bunny (I would guess the latter, based on his behavior) then be very careful. A cottontail has much higher prey reactions than a domestic bunny will, since it is bred into them to be afraid of dogs and other predators (while we have bred a lot of that reaction out of domestic bunnies). If he starts to react strongly then take the dog away. You can even work with the bunnies the way you do with the dog – let the dog get a little closer, then give the bunnies treats so they associate the dog with good things and only move the dog closer when they are calm.