1-For Ar for Japan, we have to compromise otherwise we can’t add anything to it the best 3 candidates are Type 2 with 6.5 mm ammo (SMG with bigger ammo than normal small 6.5 and smaller than 6.5 Arisaka people from the forum already made topics about it), Dutch M.15 Madsen gun(captured)(With shortened barrel and chambered in 6.5x53R dutch mannlicher ammo, it would be similar in performance and role to Fedorov AR soviets have.) and lastly STG-44 (Japan bought 6 I don’t see them being in the tech tree but as a gold order why not)
( Dutch M.15 Madsen gun)
2- For Bar like guns Germany could get MKB 42(G)
and the Soviets could get Kalashnikov light machine gun
3-For low-BR semi-auto for Soviets 1918 Tokarev mosin-nagant semi-auto conversion(there are carbine and full length version)
4-For high BR Japan handheld AT
Type 4 with 90 mm ammo (120 mm pen )for BR 3
and for tier/BR 5
Type 97 with Ji-Te Dan
Its 20 cm granade that pens around 220 to 250 mm
5- High cap SMG for Axis there is VZ-38 SMG with 96 round drum but has slow rate of fire(500)
6- about rifle grenades on semis
The germans didn’t have anything like that at least from my research but they put grenades launchers on MKB 42s and STGs and also Mp43s
For soviets I couldn’t find anything on semi rifle but they put grenade launchers on AVS-36s
7- For scoped semi-rifle for Japan I don’t think they will need it as they could get Type 96 and 99 with scope
8- The scoped automatic rifle for Japan is gonna be type 96 and 99 with the scope and for Americans, I hope you like Thompsons cause we gonna get yet an other Thompson