So, what if Takahashi or someone of like mind had pioneered his quasi-New Deal approach back in '27,
That's not completely daft, but it needs some spadework. What Takahashi did in '31 and after was very bold, and the only reason he got away with it was because the government was utterly desperate. In 1927 it would have been far outside the bounds of acceptable orthodoxy. Just going off the gold standard for a couple of years (which they did) was considered pretty risque; it was accompanied by loud and firm proclamations that they'd go back on it just as soon as things stabilized. Fiscal stimulus and deliberate inflation... whoo. Very heady stuff indeed.
With no invasion of China (in the form of occupation, looted/raped cities, carved off puppet states--but lots of Japanese business enterprise, )
Well, there was lots of Japanese enterprise in China OTL.
The tricky bit here is getting a stable Chinese government that (1) isn't actively hostile to Japan, and (2) is acceptable to Japan. Chinese nationalism is going to resent Japan as an imperialist foreign power taking advantage of China; Japanese military and economic elites are going to be reflexively nervous of a strong centralizing Chinese government.
Maybe not impossible, but harder than it sounds.
Doug M.