Problems with a japanese side
Hmmm yes that is a good Nambu 100 substitute... with modification.
I think K98 is superb weapon, and very versatile for world war 2 skirmishing. However the Bolt is hooked/curved and that is not as correct as Mosin Nagant which has straight bolt like Arisaka... also the K98 is a bit shorter.
However Price is big issue so I wouldn't mind slightly Germanic looking Japanese side... especially since in some campaigsn the Imperial army and navy used captured Chinese Mausers.
Arisaka and Mosin rifles are hideously expensive and rarer than K98. I think Dboys spring is the cheapest but other companies like GandG and Marushin and Umarex make K98 in gas versions too.
In fact what is another good scenario is Shanghai warfare. Because in Shanghai, Nanking etc the Japanese went up against Chinese troops like 88 Division who were equipped like Germans Same helmets and rifles... I think they only lacked MG42's and tanks but had everything else... Even german officers/advisers... this was 1937 so just before world war 2.
The Japanese also had lots of SMG's at that battle for street fighting in Shanghai it was Stalingrad of the East... The Japanese pioneered house to house spray and pray tactics using Mp18's Lanchesters and Italian as well as homemade Nambu SMGs