Maybe I’m just face-blind or being dense but the photos from the scene of the crime look like a different dude than the ginning hostel check in guy. The jackets and backpacks are different. Although people can have multiple jackets and backpacks. We don’t see much of the shooters face but the eyebrows look different. Although, people can pluck/shave eyebrows. I guess the happy hostel guy would have come forward and been like “WTF?” and “I have an alibi” if it wasn’t him?
The killer seems pretty competent, having multiple jackets and backpacks and switching things up to make it harder to track him doesn’t seem unreasonable.
I thought you were joking (missing /s) but judging by the comments you mean it?
I don’t think this sounds plausible, no. You’d try to make yourself look completely every time if that were the case.