THEORY;
Trump is endorsing all his Senate, House and state officials as we speak. If he were to return, it would be just after the mid-terms. I'd say January 21, 2023 would be a really good guess. Giving him 2 yrs of fake president Biden's remaining term and then as the likely MAGA candidate, a full second term in 2025.
We know there will be a red wave come mid-terms, given the Trump endorsement-to-win primaries (93%!!) That sets the 6 year stage for Legislative, Executive and Judicial branch MAGA.
Now, here is a MAGA hypothetical.
If MAGA supporters win back the majority in the House, they could vote Trump in as Speaker of the House. Law says; An average citizen can be voted in by it's members as Speaker!
Trump could then bring articles of impeachment against Biden & Harris. He could also do the same for corrupt House and Senate members, as well as SCOTUS and other agency corrupt personnel and department heads.
Can anyone imagine the multiple articles of impeachment to finally DRAIN THE SWAMP? Liberal leaning C-SPAN that televises these hearings would have a major case of the hives! Haha!
Just to clarify - a VP vacancy doesn't elevate the Speaker to VP - though it does make the Speaker next in line for the Presidency while that vacancy exists.
Of the names you listed, Stefanik has the inside track as she is already in Congressional leadership, and she's a woman. McCarthy and Scalise can't be ignored - in fact McCarthy is almost guaranteed to be voted in by the GOP conference. He was already passed over once in 2015, - and as much as we cast a scant eye toward his leadership style, when it comes to Congress, he has worked his way up, paid his dues, and made all the right connections.