China is by far the biggest gaming market, almost 50% of all steam accounts are Chinese. There’s more money to be made by appealing to Chinese tastes than any other market in the world. That’s my guess anyway. This game is Chinese though, so they could just be like, appealing to their own market through crossovers, if that’s what you mean when mentioning the other games.

Dunno, the story of sun wukong has been widely adapted over all of media in diverse ways. Dragon ball & songoku is the most known one maybe, but there's tons of wukong adaptations in games, the trend is not recent at all. It's a champion in League too. He exist in Dota2…

Cool character with a cool story.

Tbf, I'd hardly call the Warframe reference recent. Didn't he come out like 5 years ago?