If FFO Italy can either stay neutral or not
In the latter case I imagine Libya to be lost to Mussolini's cause as it cannot be supplied.
The MN is easily RM's peer and there would be no OTL Italian shipping route along the Tunisian coast. With the Italian DOW being a spark of inspiration on Duce's part, Libya does not possess stocks for operations. A self administered POW camp, really. Once gasoline runs out it could be ignored (but the Allies need a victory for propaganda, however ...).
Allied convoys should be able to run along the length of the Med, with eastern Algeria and Tunis providing air cover over the Sicilian Straits.
Would FDR impose an embargo and fiscal sanctions on Japan without the occupation of FIC, thus ensuring Japan's strike south? Would Japan strike south without the sanctions? I'm not knowledgeable enough.
Nevertheless the FIC should be better prepared.
Although the guys who wrote FFO had the French evacuate IMO ASB numbers of men, I still imagine low six digits as possible. Even if predominantly REMFs, then these would still provide the arty/recce/trains/signals/engineers to formations with non-French bayonets. The weapons would have to come from British or US factories, though.
As long as France keeps Haiphong (open) the RR to Kunming can be used to supply the Chinese.