When a patent expires due to non-payment what happens to pending child continuation applications and an appeal of a child continuation application? I assume the expire patent is not valid at least while expired so there would be nothing for the applications to tie to. Will the PTO still consider the application from a couple of years ago and an appeal of an application from several years ago?
Child applications / patents are separate issues. They do not share procedures. So the answer is simply: It doesn't matter if the parent expired, lapsedor got invalidated.