I went to Japan during the lockout year and saw a few games. I talked to some guy who said the Nikko Icebucks are owned by a paper corporation, and the players are employed by the company during the off season. I don't know how accurate this is, but if its true, you might be able to compare some Japanese salaries against what the minor leagues pay.
Also don't forget there are three countries involved. There may be discrepancies between them.
I know this doesn't really answer your question, but I hope it helps.
according to THN, who did an article on Tyson Nash, the players (at least the Japanese teams) are employees of the owning paper company, and most of the domestic players work at the factory in the off-season (wether they are "token jobs" though i dont know)
Also they are only allowed 2 imports per team
Also, i read in a report by Mike Milbury when he visited the Chinese ASL teams a couple years ago (i'll see if i can find the link), the players on the Chinese teams only make about $120/mth...that seems a little low though