Hey, that can be frustrating. This is a very rare occurance, but I do see it happen a few times a year.
Once the Certificate of Title has been issued in your name, you are the legal owner of record. The motion to stay is the thing to keep an eye on right now. In Florida, a stay pending appeal usually requires the former owner to post a bond, and if they did not post one, the stay likely will not hold. Just make sure you have an attorney respond to it so it does not sit there unanswered.
On the appeal timeline, 6 to 18 months in the Fifth DCA for Orange County is realistic, but appeals after a Certificate of Title has already been issued are extremely rare and almost never succeed. Out of thousands of auction sales I have seen over the years, this type of situation comes up maybe a handful of times. The surplus disbursement motion is a separate issue and should not affect your title or possession rights.
That said, with multiple motions in play at the same time, this is a good spot to bring in a Florida foreclosure attorney just to make sure everything gets responded to properly. The cost of getting the right advice now is a lot cheaper than leaving something unanswered. But big picture, this is a very unusual situation and not something buyers should expect to deal with at a normal foreclosure auction.