It's brilliant, but regarding Beijing: AFAIK Peping was the KMT-Republican name for the city, emphasizing that the capital was in Nanking. I'd think the Qing would refer to Beijing as Peking over Peping.
Christ. Screw Wade-giles. It's like they had to create the most unintuitive system imaginable by man.
Glad to see someone who knows their shit about the Warlord Era here! I certainly don't lol, which was why I put my trust in the CIA when I went to labeling the cities--assume the map's made by a Yank, by the way.
As for Peking and Peping, eh. I just added both because I can't be assed to check the beef between the KMT and the Aisin Gioro

. I saved most of my effort in researching the names for Inner Mongolia and Tibet.
(Especially Tibet--seriously, getting the Tibetan names of the cities in the TAR took me an hour, including the time it took to actually corroborate what's on the maps. This part's also hard because every map of the region from at least 1980 basically used only Tibetan Pinyin or something, which an actually sovereign Tibetan nation probably wouldn't use.)
Admittedly, Wade-Giles isn't as bad as Wylie for Tibetan, where pronunciation and transliteration don't even match lol
By the way, a little shoutout (to the Kaiserreich team!) : I personally am a bit dissatisfied at the fact that Tsingtau (Shandong area) is part of the AOG, a company, while Weihaiwei is under German Governmental control (even if autonomous) - because Tsingtau was the german state-controlled area in WW1 while Weihaiwei was a British Concession.
Just a foreword from here: I'm not part of the dev team. I just like the setting a lot, so much so that I made no less than three maps of it.
As for Weihaiwei, it probably got assimilated into Deutsch-Ostasien because the Germans want a little bit more control over the Chinese coast, particularly the part that borders the Bohai Sea. At the end of the day, AOG's just a conglomerate with
de facto suzerainty over a bunch of concession ports in China--contrast to Deutsch-Ostasien, where most of the German military presence in the Asia-Pacific is concentrated, and with a larger population and industry base. It'd make sense for Germany to integrate Weihaiwei to their little "army with a state" in Indochina for strategic purposes, rather than cede it to the AOG for their Board of Directors to do with it as they see fit.