"My understanding is that casinos eventually obsolete their LE issues."

Very few casinos have recalled LE's.

"With all of the Limited Edition chips out there what do casinos tell their dealers regarding accepting LEs for table play? How would they be expected to know what chips are obsolete and which ones aren't. Especially if it comes from a different casino."

Most floor people have no idea what is current and what is obsolete. If its $25 and down they take it. I have seen them take fantasy chips.

"What does a casino do when they receive back an obsoleted LE chip? How do they account for it?"

They destroy them and write them off. Happens all the time. Obsolete tokens are a real problem.

"Is the list of obsoleted chips published anywhere?"

Not that I know of.