Well yeah. Sino Japanese coalition isn't going to be landing in San Francisco Bay anytime soon but I think a level of cooperation between China and Japan and some organic Pan Asian anti colonialist sentiment rising isn't out of the question. And of course it would be completely blown out of proportion. I imagine Wilhelm II would especially attempt some shenanigans since he was absolutely terrified of some Asian threat and had been eying colonies in China forever.I think that a lesson here may be that Western fears of a Chinese-Japanese alliance to overthrow Europe and America might not have been entirely based in reality.
On a different note, I've been examining the possibile results of a Sino Russian war and uh, it doesn't look good for the Chinese. It's just too large of a front with Russians probably being able to seize Xinjiang without too much a of problem. I don't think Zeng could reform the entire military to the level he needed by then instead of just certain armies that would be planted more in the east anyway.
Also what could be interesting is if Japan's ambitions in Korea are checked and there's a sort of informal agreement with China, there's still options for Japan to expand, specifically a certain colony owned by a third rate power. That's right, the Philippines! But interesting, Germany was also really interested in getting the Philippines. So you have that as a potential point of conflict if one can get there before the other.