So if Spain doesn't become a republic, then maybe the Hapsburgs rule Spain?
There is a gap of centuries seperating the POD and the events you are talking about. The problem is, by the time you get to the POD, you have 350 years of Spanish history, much of it directly effected by the Bourbon monarchs who In this timeline would not exist. Juan Carlos would never exist because his father, grandfather, and all the Spanish Bourbons back to Phillip V would never be born. And Franco (along with pretty much everybody else from his time) and the political situation which allowed him to rise would never exist, because of the butterflies caused by three hundred years of different Spanish leadership.
BTW, Susano, Phillip II died in 1598. Unless you mean Phillippe, duc de Orleans, who would become dauphin upon his brother's death. Although he would have been Phillip VII of France. I agree, however, that whether or not absolutism comes around would be an interesting feature of TTL