So unfortunately, it is too soon to expect to be establishing firm building blocks for bonding. She needs to be spayed first and then one month after then (when hormones settle and she is recovered), you may then begin the bonding process, starting with short introductions in neutral territory: https://binkybunny.com/infocategory/bonding/

Presently, and for the next several months, you can house them side by side with a gap (to prevent injury across bars) and rotate their free roam time, but there should be no attempts to have them out together or have them meet directly. Her hormones are a very big facilitator of territorialness for both her and Junior, even if Junior is generally a docile boy (as you noticed).

Any positive relationship you may observe between them would be a “baby bond”, also known as the false bond. It is not the same as the bond in a bonded pair. Baby bonds come about because the younger rabbit is not yet hormonal so territorial, dominance, and mating urges are not in the way, creating relationship tension; however, the process of puberty and hormone emergence is invisible and unpredictable, so baby bonds are unstable and unfortunately there are many cases of owners reporting “My rabbits were so cuddly for months and all of the sudden they are fighting and hurting each other.” — At this point, it appears a baby bond isn’t even there, so all the more reason to keep the separation.

That being said, as long as the gap is there and they cannot get to each other, over time, her presence can be a positive stimulation for Junior during these months before her spay (at 6mo).