Looks like a BN to me.
I find that BN's can become aggressive if they aren't getting enough to eat, but sounds like she's just territorial which I also find is pretty normal. I wouldn't worry about it much if he's getting enough to eat too. Or you can take her out and rearrange things so she doesn't have a territory anymore and see if that helps when you reintroduce her.
Also, BN's don't get their bristles until around 4 inches so you could potentially have two males in the end.
I find that BN's can become aggressive if they aren't getting enough to eat, but sounds like she's just territorial which I also find is pretty normal. I wouldn't worry about it much if he's getting enough to eat too. Or you can take her out and rearrange things so she doesn't have a territory anymore and see if that helps when you reintroduce her.
Also, BN's don't get their bristles until around 4 inches so you could potentially have two males in the end.