Based on what is best for the Bills as a football team, if they are not reasonably sure this is false, they should sign another punter and cut Araiza. It is too much of a distraction to keep a punter who hasn't even been on the active roster yet while this plays out.
This may not be what is fair, but it is the best decision for the team. The draft pick is gone at this point. There will be a cloud over him for some time which is bad. After that either he will be cleared and resume an NFL career or he will not be cleared and suffer the consequences.
Basically the Bills can take bad publicity for an upgrade at punter (which may not be permanent if he is found liable/guilty) or they can have neutral publicity for an off-the-street punter. The latter seems right.