If any of the Slayer fragments do have an objection to Simon's presence in the house, they would scarcely get the chance to take it up with him. In contrast to his assertive, almost confrontational personality during his first stay in the Slayer house, this time around he's so unobtrusive that sometimes it's easy to forget he's even there. He tends to avoid the Slayer house during times when he knows that a lot of people are going to be there, preferring to spend that time out of the house going on long jogs.
When Simon is seen around the house, it is often in the company of Ally. Whatever he had with Ally is clearly persisting, although in comparison to the past "in your face" type relationships (Ally's among them) that have taken place around the Slayer house, this one is much more discreet. It's around Ally that Simon seems most like his old self, joking around with the others and speaking his mind freely. He is also fairly comfortable around Teresa, maybe because she wasn't as closely tied in to everything that happened with Sabrina. However, he treads especially carefully around all the other Slayer fragments, aware that some of them may not have the highest opinion of him. This is best seen around Jack, who is definitely suspicious and mistrustful of Simon.
Simon gladly participates in patrols, and seems to look forward to them. His hard work with Ally in the training room (and a few early fights when he gets pretty banged up) pays off, and by the end of the summer he's a much better defensive fighter. Otherwise, Simon goes to great lengths to distance himself from reminders of who he used to be. Ally's best efforts to get him to patch things up with Anthony are not successful (although they do avert a screaming match or two), and he never goes to visit Nat. When Anthony and the remaining demon hunters leave town in the middle of July, Simon doesn't say anything about it, but is obviously upset.
For much of the summer, Simon doesn't really seem to know what to do with himself. It eventually gets around to everyone in the Slayer house that since Anthony was in charge of the demon hunting group's finances and has now left town with said finances, he's pretty much flat broke. But seeing as how five years of professional demon hunting experience do not look good on most resumes, Simon decides to earn his keep by doing chores and odd jobs around the Slayer house. It might not be what he had in mind when he came to Teffelsburg, but until the future makes his path clearer, he'll stay where he is.
(OOC: If you guys get the chance I would love to know about the PCs' reactions to Simon living in the house for my own GMing/roleplaying purposes, since I know this kind of got sprung on some of you.)