Just wondering, what/are there any brand operating in Japan at all?

You mean CAR brands ? If so, it's really easy to answer:


JAPANESE CAR BRANDS:

Nissan;
Honda;
Suzuki;
Mitsubishi;
Mazda;
Toyota;
Daihatsu;

And some more !

Ugh thats not even remotely what I mean; Im refering to Chinese brands

Just wondering, what/are there any brand operating in Japan at all?

No. Only parts so far.

Are Chinese brands manufacturing cars in other places besides China?

Too many to name them all, especially if you count assembly plants also. Chery has factory in Malaysia, JAC cars are built in Ethiopia,... Check the forum for further info.