I would think Portugal would be the perfect "Neutral" partner that would be able to import export and be an intermediary between countries in South America. Sweden and Switzerland are basically minor mirrors of the Portugal situation.
Greece should be the farthest thing from Mussolini's mind as he now has the whole NE corner of Africa. His raw material discoveries in Libia and the acquisition of Egypt should put the Italian economy on firm footing. Plus his resources should be spent improving the infrastructure in this area. He also still needs major improvement in his armed forces from and equipment and training standpoint.
A good point about Portugal's position facilitating trans-Atlantic trade.
I fully agree that Mussolini should set aside further expansion. Judging by his historical actions, though, what he should do and what he actually will do are not necessarily the same.
You're right. This undertaking would be difficult while you're in a shooting war. This would have been needed to be planned out prior to the invasion of Poland and then phased in over the proceeding years. Where this will be very profitable is in the Polish territory with large relatively flat farmland and then in the Ukraine area. They could settle that area kind of how America did with the west; every German moving out there gets 200 acres and a tractor! That would kick start your food production quickly.
A program of agricultural mechanization before the war was something I actually did consider. The thing is, I'm trying not to have Wagner be such a skillful leader that he makes the correct decision at all times, meaning that he does on occasion make subobtimal choices. That said, the suggestion will be noted for possible use after the SU's defeat, which also raises the possibility of using the former Soviet tractor industry.