Wow, the last one looks really good! Only thought is that a lot of the turrets seems very american. I got the impression that Koko was more closely aligned with the IJN?
Also, do you know what Sagami means(I don't know, I'm just wondering)?
Yes, the turrets looks quite american, that particular appearance is supposed to be the consequence of a reverse-engiinering on the wreck of USS South Dakota after the second naval battle of guadalcanal (14-15 november 1944 in the timeline i'm working on where WWII start in september 1940, and ends in august/september 1953 with Pearl Harbour beign attacked in december 1943).
Also Koko itself has indeed strong ties with Japan, (90% of her population is of Japanese origin as they where the first to colonize the archipelago before the Edo period) but i'ts not a completely free nation: it's something between a puppet state like Manchuko and a real indipendent country, and it's forced to follow the same foreign policies of the empire despite a quite strong opposition within her population and governement; this added to the controversial sinking of battleship Yashima in 1948 ad a subsequent coup d'etat will lead Koko to change faction around 1949, so design influences from US units will be not to uncommon.
This is obviously a loose and quick summary, i'm still not too sure to turn everything in some sort of AU, but anyway i still need to organize the background a bit more first.
About the meaning of the world Sagami, i don't know either unfortunately, i'm not really into japanese language despite beign an usual anime watcher; i have a friend who knows japanese very well tough, i will ask him if i remember.
Aniway, i've taken the name Sagami from the
japanese province with the same name.