>

Good move.  Make him a global focal point.
I can't see Xi stepping into Ukraine. >

what would happen if Xi goes to Kyiv to show his public support for Zelensky? >

That would be counter to what he has been doing: increasing support for Russia.  source >

then what would be the appropriate way for Xi to respond to Zelensky's invitation? >

Nothing. China is in that weird spot no matter what action they choose, it will do poorly.
1) If China support Russia--well, possible sanctions, possible nothing. West opinion of China will not improve.
2) If China support Ukraine-- No additional benefits, hostile Russia on their northern border, western opinion will not improve--and certainly wouldn't help get Taiwan back. if Russia collapses/fall into a western controlled puppet (Yeltsin II), it wouldn't help China either. 
So basically geopolitics dictate China to sit on the fence. No matter who wins in this war, it is unlikely they can cut China out from the future. 
So the answer is to do nothing. >

China also undermines their own geopolitical position if they support Russia too strongly. It tarnishes their legitimacy if they don't support territorial integrity and opens the door for more nations to support Taiwanese independence. >

Taiwan is always considered part of China from China point of view. In their eyes, you can support other countries territorial integrity and demand eventual reunification of Taiwan. 
But lets face it, it is not like China (and everybody else) took on Americans when they stormed Iraq or when Russians charged Georgia. Talk is cheap. 
Most of Taiwan's western allies will not change their mind of China-Taiwan issue, nor will China. Whatever happen in Ukraine is irrevlant. >

Yes that’s the point. 
Supporting Russia is saying territorial integrity is not important because they have invaded and annexed parts of a neighbor multiple times. China’s justification for its Taiwan policy is territorial integrity. 
You’re right that it won’t make a difference though. No one in East Asia really trusts China anyway aside from maybe Singapore, so no one expects them to have consistency in their policies. >

Singapore does not trust China. Singapore’s foreign policy is to trust no one. >

Ukraine about to join the Belt and Road Initiative >

They were already part of it, but the war derailed the ongoing investment project.
As a side note, it's very likely Ukraine will take advantage of Chinese help for reconstruction. They don't have to be tied solely to the West for what's going to be a long, costly rebuild of their country. >

Don’t forget that technology transfers from Ukraine — not Russia — formed the basis of many Chinese military equipment. >

Yes. The most striking example is probably the Liaoning, the first Chinese aircraft carrier that is in fact the rebuilt Ukrainian/ex-Soviet Varyag kutnezsov-class carrier (though bought under cover as a floating casino). >

Y'all gonna have an aneurysm when you find out Ukraine and China have good relations. >

Welcome to the black and white world of the Reddit hive mind. >

Who are you declaring yourself superior to in this comment? >

clearly the implication is the average redditor >

Vague response from Xinnie the Pooh about how much China cares about 'world peace' but respectfully declines to help facilitate it actively, incoming in 3,2,1... >

We are just now hearing that China is currently Bing Chilling on the situation.