@Kaarme Same reason on how the tanuki got the job working on the same company on the same department on the current economy not to mention he is hired because the boss is grateful he save him. The plot demand it.
@Jeirien To be fair, in the case of the tanuki, she was already revealed to be really into Nakano, and he's also the only one whose willing to help her through her incompetence due to inexperience.
The Kouenji thing seems a little bit out there, but if it's used to expose more character traits, it could end up making sense.
Feels like the author forcibly maintaining the status quo by having Kouenji move in next door to their new place.
Same thing too with Fukuda-san with the workplace transfer.