Let's not jump the gun & wait for the outcome of Trump & Xi discussions/agreements. My gut feeling is that there will be "trade-offs" by both sides, & hopefully satisfying for US & China. Presently, Trump appears to be listening to a better set of advisers, although he appeared unpredictable in recent times. Being in business Trump would know negotiation techniques and on how far he could go. Interesting for us observers.... Anyway, let's await the outcomes - Peace must be given a chance to succeed.
Other than trade, where Trump may very well get some reciprocation for American businesses (and it's about time!), I don't see Xi giving anything substantive on Taiwan, DPRK, and SCS.
On North Korea, China will not destabilize that government sufficiently to risk collapse. Anything Beijing actually do would likely be more form than substance.
US might sell Taiwan some weapons, but nothing that would make any difference in the grand scheme of things. Taiwan's road to economic and military security lies squarely through Zhongnanhai. If the crazy Greens declares independence, then Beijing would bring it back into the fold by any means necessary. Taiwan is part of China. Full stop.
As for the South China Sea, it's all over but the shouting. Reckless neocons like Senator McCain and Admiral Harris might convince President Trump to do more FONOPs, but they wouldn't change the fact China is relentlessly and methodically consolidating its strategic hold on the greater SCS area, and US would have to start WW3 to try and force it out.
Other than that, Trump and Xi should get along famously.