In my experience, bonded bunnies don’t “play”. Bunnies in general don’t “play” the way we think of for dogs and cats, so it’s not strange that they wouldn’t play with each other. They definitely interact, almost constantly, but it’s snuggling, nudging each other, checking in, that sort of thing. My girl also chases my boy and nips him a lot. I feel bad for him, but it’s how they interact and it doesn’t cause fights (I do yell at Hannah when she does it).
The chasing is often related to an attempt to hump. Fixed bunnies hump out of excitement or to show dominance and if the other bun doesn’t want to be humped, a chase can start. Bonded bunnies can exhibit this behavior, but bunnies who aren’t bonded do it too.
At this point she’s really too young to bond with another bun. You can let them get used to each other, but she will mature and may change her opinion of her new friend until after she’s fixed.
Do they stay in the same cage? A bonded pair cannot be separated – they need to be together 24/7. A pair that is in the process of bonding, as your pair is, should stay in separate cages so they don’t fight when you’re not there.