As others have said, and I think I remember even you agreed.... I'm sure it IS slightly escalated because they are women..... but frankly I would venture to guess you'd be just as annoyed if it were two male neighbors, but the story was otherwise 100% the same. As you've said, you don't suspect anything untoward would ever happen between them, it's more the fact that they intrude on what is supposed to be your one on one time with him. That and the fact that he doesn't seem to see any problem with that. I would imagine if it were his male buddies doing the same thing you'd be just as annoyed.
I can understand just how you feel on that. Like I said earlier in this thread, that sort of thing would annoy me if I were in your boyfriend's position... and I don't have a girlfriend. I wouldn't mind having friends, even female friends, but I wouldn't want them THAT up in my business all the time. So, yeah, I get it is more a matter of boundaries and more so of your boyfriend showing some respect for you and proving you are a priority.
Sounds like he's at least made an effort recently. Personally, I'm still slightly annoyed FOR YOU based on the lengths you had to go to get him to this point in the first place.... but, Hell, I suppose if he actually makes an effort to be better about it that is all that matters. I hope he continues to improve and is able to settle into an arrangement that keeps everybody happy. It would certainly be great if you could even all still remain friends, even you and those gals.... but just with the appropriate boundaries so he isn't basically treating them like they are his girlfriends and you are the one who is just a friend. Good luck!

He's off to a good start. I hope that continues.