Deletions are now reflected* in the inbox.
There is, of course, a natural race condition; wherein you load a page with a notice right before the originating user deletes the answer/comment. That's not going to be addressed.
As for edits, we're unlikely to every reflect those in the inbox. Its a lot of trouble (technically), when you're almost always just going to go and read the post/comment.
*This is "going forward," old items that are in the inbox that correspond to deleted posts or comments will remain. At least for the time being.