Germany and Central Europe will be a mess for a while. Italy has the chance to secure its position, while keeping warm(ish) relations with France and the UK, maybe helping financing the Suez Canal? It's a bit soon for colonial claims (and Tunisia isn't really worth antagonizing the French over).
Germany (or better "Germanies" at this stage) and the Habsburg empire will be in an unsettled state for at least 18-24 months. As you say, it is a good opportunity for the Italian Confederation to build up a diplomatic presence and a soft penetration in Bavaria and Baden; setting up communication channels with Hungary would also be useful, but in this case there would be no overt diplomacy of course.
France is equally unsettled: I believe that the results of the elections of April would not be substantially different from OTL (let's say 20-25% legitimists of different flavors, 55-60% moderates and 15-20% democrats). IOTL, the months of May and June were the critical ones: French politics turned to the right, and the blame can be shared almost equally between the democrats, who were disappointed by the electoral results and quickly turned to extra-parliamentary opposition, and the moderates, who were convinced that the only danger to the republic would be come from the left. I would argue that the news coming from Italy, where the moderates and the democrats have apparently found a modus vivendi, might influence the politics in the Assembly too, the more so if the combo of diplomatic rapprochement and personal efforts I have outlined in my last post is put in place. I am not saying that French politics will be totally changed by what is happening in Italy, but there will be some influence for sure (and hopefully it will be a positive one: avoiding or at least minimizing the Bloody Days of June would be a great outcome).
The future Italy (the roadmap of which has been roughly sketched in the Convention at Isola della Scala) will take some time to coalesce completely. It is however quite obvious that such an Italy would be firmly positioned in the field of the Western Democracies: UK and France, obviously, but also the USA (making allowance for the geographical separation). Austria will never be a friend, at least in the medium term; the same is likely for Prussia, in particular if the spadework in Southern Germany produces results,; Russia does not necessary need to be hostile (leaving aside the aversion of Nicholas I for democratic revolutions), but at the same time there is no great benefit which might be gained from befriending them, and certainly a Russian expansion in the Balkans and Anatolia would not be aligned to Italian interests.
I believe you underestimate Italian presence in Tunisia (which is already there at least since the end of the Napoleonic wars, and even IOTL grew quickly in the 1850s and 1860s) and at the same time overestimate French interest in Tunisia (which IOTL grew in the 1860s). I would suggest looking at this:
https://www.istitutoeuroarabo.it/DM...-in-tunisia-tra-l800-e-la-prima-meta-del-900/ (in Italian, sorry).
Of course, Italian position in Tunisia must be secured in the 1850s, but I do not see any great difficulty here.
Finally, the canal of Suez: it is obviously in Italian interest to be involved from the beginning, and setting it up as a joint venture including also UK and France might result into an early completion of the canal (IOTL the British were against the canal, which was seen as benefitting mostly France, and proposed a railway linking Port Said to the Mediterranean coast as an alternative).