Lol oh my goodness poor Sebastian!
In all seriousness, though, maybe that is how he'll react, to a degree. I usually draw from my own experiences with gliders, so I'm no expert but I do think sometimes similar experiences help us know about other gliders. In my circumstance, when we got Luna we also got her (filthy, horrible, inappropriate) cage before we knew how terrible it was. I think maybe they had never ever cleaned it or the fleece they were using for pouches. In other words, it smelled. And I got it at night, so I put it two rooms away from my quad instead of cleaning it. Well, let me tell you, my quad barked. And barked. And barked. For hours. And when I went to check on them a number of times I had never seen Clare looking so scared. At about midnight we put that stupid cage outside on our back porch (in the snow). Anyway, my point is that in this situation my quad acted the same about the new glider and not that this will happen with Sebastian but they never accepted Luna.
What I am inelegantly trying to say is your Sebastian may be scared and this has in fact been very helpful because now you know to take it slow with him. Maybe you'll want to put the girls in a different room at first, so they could probably hear each other and gradually become aware of each other. And maybe for scent swapping you might want to just put some of their stuff near the cage at first, but not inside it. This is good! Now you know he's a nervous little feller when it comes to girlfriends and he'll need time to adjust.