Oz also pointed out in IRC the opportunity for stories about fighting in the rural areas in the south of Myroria/north of Ozia. It could even be possible that the people living in the mountains in that area, isolated from their respective societies, might be more interested in fighting whatever intruders were encroaching on that land rather than each other (assuming Ozia and Myroria are on opposite sides).
I'll link Gulliver to this thread as well. As a fascist dictatorship, his nation would almost certainly be itching to fight whoever could make the war industry churn.
Here's a list of political systems for nations that might participate. If I'm misinterpreting yours, please correct me. Alliances will probably work best if the regimes of the nations in them are not built on opposing political systems.
Eluvatar: parliamentary democracy
Ozia: one-party communist state
Rykkovaa: fascist dictatorship
Myroria: constitutional monarchy, very powerful monarch, weak legislature
Kerras: liberal democracy
al'Khem: aristocracy/caste system (unsure of the situation in the 40s-50s)
Megatrine Republic: unsure of the situation in the 40s-50s
Jutensa: unsure of the situation in the 40s-50s
I think any sort of conflict starting in Jutensa would involve colonialist powers being the aggressors (but I could be wrong!) Myroria could be itching for power projection as it recovers from the original Great War, Ozia could want to project its own political power in a historical colony, or the Megatrine Republic could want a foothold inside Cefnor rather than being confined to the outer rim. In a similar vein, colonialist powers could try forcing a regime change or outright annexation on Funkadelia.
Just brainstorming though! There are any number of coalition combinations, or casus belli that could work.