Ok more info to come soon but just a quick bit of info.

If the mod takes place post 1300 then Sicily should be in the control of Aragon. The War of the Sicilian Vespers officially ended in 1302 (I believe) although fighting between the House of Anjou and Aragon continued long after this. If this is so, then Sicily should be able to import Aragonese units from this period in the game (so if there is a port, then Iberian units could be trained by the Aragonese).
If you count Sardinia as part of Italy, then this was invaded by the Aragonese in 1323-24 having been promised to the Aragonese by Pope Boniface VIII in 1297. Again, true gonvernship of this isle would not be an actuality for some time.

Proper unit info for some other factions a wee bit later, but this should give you an idea of units for the Sicilians/Aragonese.