My POD is now Hundred Days and a little bit of luck for Murat ; so first Congress of Vienna only.
Well, the Bourbons will be pissed off, not just Ferdinand and the court in Palermo. In Paris, Louis XVIII is going to be livid since this move would singlehandedly reduce significantly the Bourbon influence in Italy (in fact, until Maria Louise's death, they would be without any territory in mainland Italy, since the duchy of Parma would be hers for life before reverting to the Bourbons iirc). It could therefore be construed as Austria's effort to become the sole hegemon over the entire peninsula (since Murat would owe quite a lot to them, since it was Metternich who pushed rather actively to bring Murat into the fold. Therefore, this could result perhaps in less cordial Austro-French relations and perhaps Louis XVIII would be at least a bit more willing to work with the Russians (although Saxony would still loom large if Russia still supported Prussia's designs).
It might also make France a bit/somewhat more intransigent on the matter of the colonial possessions, since Louis XVIII would want to get and have to show something in return for a backing down on the matter of Naples. This could be another reason to lead France somewhat closer to Russia, especially if Alexander has more success in building ties with the lesser naval powers and supporting them in the negotiations with the British (and if Alexander managed to get the marriage of his sister with the House of Orange instead of that of Princess Charlotte, Alexander might decide to stick more to this policy and thus pursue it more when it came to France).
The Spanish would also be rather unhappy, since Ferdinand was from their Bourbon branch and because Murat would perhaps try to push for the territorial gains promised to him by Neipperg (and most likely materialised in the Papal states, whose territorial integrity the Spanish government was perhaps the more ardent supporters of).
Sidenote: Now, if Murat really managed to get territories in the Papal States, Metternich could perhaps push for Romagna (considered until somewhat late iirc to be open for redistribution by right of conquer St by the Coalition) to be given to Eugene de Beauharnais - which would please the Wittelsbach somewhat, since the possibility of Eugene getting compensation in Germany which would then be counted as part of the overall Wittelsbach gains promised in Ried would be removed and the Wittelsbach would remain a more prominent dynasty with connections outside Germany. However, the value of it is perhaps doubtful, since after late 1813, Bavaria was rather closely attached to Austria and the main problem was in Württemberg - but perhaps this extra goodwill might make it somewhat easier for Metternich to convince the Bavarians to accept territories west of the Rhine as part of the compensation.
(hope my comments aren't wrong or implausible)
