If he does not go back to Napoleons side during the hundred days, will he still be removed from the throne on Naples? And if he is, will he be given another kingdom to rule?
1-Not sure: the Bourbons wanted their Kingdom back, and he was not a great diplomat, nor was Naples particularly significant in the greater European balance of powers. It appears that he had some sort of deal with the Habsburgs, but feared that they would not live up to it. Still, if he promptly retreats from the parts of the Papal States that he had occupied and luck is on his side Austria might allow him to keep his throne (The more divided Italy is, the better for them after all. He might however lose it to nationalist agitation (trigggering Austrian intervention of course), for example in 1821 or later, if the more radical italian liberals come to see him as a "foreign usurper" or a "traitor of the Napoleonic/Revolutionary ideals". On the other hand embracing the italian liberals/nationalists would trigger invasion from the reactionary powers or revolution from the more conservative segments of society, inflamed by clerical and bourbon propaganda (like in 1799 against the Neapolitan Republic). He has a very thin line to walk, but could theoretically succeed, and I am of the opinion that if he did, that could lead to a relatively more prosperous southern Italy, continuning the reforms started already under Joseph Bonaparte.
2-for sure not, maybe he could be given some estate and pension somewhere if he leaves the throne without fighting to the end, but after what happened with Napoleon nobody would think of a Elba like solution as feasible or desirable. EDIT: If the Pope felt really generous he could leave him with the
Principality of Pontecorvo, but it is scarcely more than a village, and would remain a footnote in history imho (at most being a center for dissidents from Naples, but would get immediately crushed if attempted anything suspicious.