I must say I find it a wee bit strange that an entire country does not activate when you attack it. Would not Spain or Portugal go to war if one of their colonies were attacked? Would not Greece go to war I Crete was attacked? I’m not familiar with the political situation in Mongolia at the time so I can’t say much about them (except they have a way to big army, no one would ever enter it anyway as it would mobilise all the other true neutrals for the opposing side).
Entering a friendly ally to get it to join is not the same thing necessarily; maybe Persia can accept Russians and Britons walking around in their country with out immediately wanting to join forces with them.
I feel this might be an area where there are a few different house rules to try out.
Another question on the same topic where someone might have some information is what is meant by ”move into” a friendly neutral? Does it have to be a land unit or can it be a plane? Can the UK activate Persia by landing with a plane from India there? Can the US just take a little detour with a bomber to activate Brazil? I think a land unit should be needed to activate them but that planes should be allowed to land in Friendly neutrals (maybe as long as it’s a non combat move (and maybe they should not be allowed to combat moves from that country).
The above question arose from the quote below in the rules preview
”Friendly Neutrals.
These territories are listed as either Pro-Axis or Pro-Allies. A Pro-Axis neutral is friendly to Axis powers and a Pro-Allies neutral is friendly to Allied powers. You may not attack, move through, or fly over a friendly neutral. During the non-combat movement phase, a power may move into a friendly neutral. This action places control with the friendly power that moved in, production moves up the amount of the territory, and the army is activated by placing the number of units specified on the territory in the territory using the friendly powers pieces.”