I think that syntactically, a few hours earlier (or, for example, yesterday) is an adverbial element here, modifying the "deleted" predictably-repeated second instance of the primary verb: ...than the drop-dead gorgeous yoga instructor was [from] a few hours earlier. It makes no difference to the meaning whether the verb is repeated or not, or whether the adverbial element includes the preposition from.
But note that of (and probably other prepositions) could be used in the cited context instead of from. I see no reason to favour one over the other in the specific example, but in some contexts it would make a difference. For example, from the 1990s might specifically refer to things that only existed during the period Jan 1990 to Dec 1999, OR it might mean starting from that time, and including everything since then.
[answer transcribed from previous comment by FumbleFingers]