1. Non-combat. Â Of the Allied forces, only UK and Anzac can do that, though. Â US can only take those islands if they are liberating them from Japanese control.
2. Â If you mean Brazil, non-combat. Â Other South American countries function exactly the same as other true neutrals.
3. Â Combat. Â You are attacking a pro-axis neutral with an Allied power.
4. Â You can, but only when at war. Â Russia has the additional restriction of only being at war on individual sides of the map. Â That is, Russia can only attack Mongolia when at war with Japan, and it can only attack other (Atlantic side) neutrals when at war with Germany/Italy.
5. Â If Spain/Portugal are still true neutrals, combat.
6. Â You only acquire the troops of a true neutral if they have been turned into pro-neutrals (of your side) through the actions of a power on the other side. Â As an example:
Germany decides to invade true-neutral Sweden and takes it over. Â Now every other true neutral in the game is pro-Allied. Â Now, on US’s turn, it can non-combat land units into Spain and take its forces as its own and the IPCs of the territory.