RE: after I add Chinese translations, will I be able to have BOTH English form visible for English detected language and Chinese translated form show when detected language is Chinese?
It should be, there is nothing special about Connections or its addons in this regard. There are coded to be translation ready … so, if the translation switcher switches the language, it should switch just like any other plugin that is also coded to be translation ready.
You do not need to do all the work to even test this … translate the strings found in the Name metabox. And then test your switcher.
The only thing I can think you might have to investigate is … I do not know how Polylang (or similar) translate category names. You may have to reach out to their support team. If Connections needs a tweak, then that can be done. I’ll just need to know what tweak, if needed, will need done. But, I imagine all fields names and labels will just work.