In my opinion, the executive orders would be invalidated and whomever assumes the office would need to re-institute them (or not, at his discretion).
Legislation, on the other hand, needs to be explicitly vetoed in order to be halted. If the President simply fails to sign it, it becomes law in 10 days anyway. The question becomes how to handle the situation -- the simplest approach is to just say that the bills were unsigned but not vetoed, and are therefore valid law. But that does set a dangerous precedent that Congress can act without Executive branch oversight. It would certainly be ugly either way -- again I would expect expedience to be the main issue. If the new President states that he would have vetoed a particular piece of legislation, it may be an issue -- if he explicitly states that he wouldn't have vetoed anything, then it's just an academic exercise anyway.
“If the President simply fails to sign it, it becomes law in 10 days anyway.”
Only if Congress does not adjourn during that 10-day window. If they do, failure to sign becomes a “pocket veto.” There aren’t that many laws this technicality would affect, but health reform reconciliation is one of these. Strictly speaking, Congress would have to re-pass such bills before they could be signed—else they’d be subject to constitutional challenge.
With the furor over health care and ESPECIALLY after members return to their districts over the Easter break, it’s not at all clear the House could secure 216 votes for the bill anymore.