In a scenario where the French Revolution wipes out the French Bourbons, who would be the monarch in the case of a restoration? Let's say everybody who died in the French Revolution dies as was the case historically. Next, the revolutionaries kill not just Louis Philip II, Duke of Orléans, but also all three of his sons, including the man who became King Louis Philip I. Now, Louis XVIII didn't have any kids, and let's say he dies in exile, as does his brother, Charles X. Given how Charles X's sons were fairly young at the time of Revolution, let's say that they succumb to the general causes of child mortality. Let's go even further, with the princes from the Conde and Conti either dying in the French Revolution or dying without issue before a restoration. I think that means the elimination of the extant French Bourbon family, though I may have missed somebody.
So, in the event that the French monarchy is restored, let's say after the downfall of Napoleon, who is available? In this situation, all of the descendants of Louis XV are dead, as are all of the descendants of Louis Philip II. The main branch of the French Bourbons has been wiped out, and the Orleans, Conde, and Conti branches are no more either. However, the Spanish Bourbons are still around, and there are many other descendants of Philip V, but Philip V had renounced any rights to succeeding the French throne for him and his descendants. In this alternate 1815, what candidate would be acceptable to all of the major powers (presumably the UK, Russia, Prussia, and Austria as was the case historically)? Who would get the throne in this scenario?