I’m a native American English speaker in his 60s. In my lifetime, “they” and “them” have always been plural in standard American book, newspaper, and broadcast English.
Admittedly (also in my lifetime), I have often heard “they” used colloquially when referring to one person, even before the concerns and requests of binary and trans people became more prominent in our public discussions.
However, I’m completely on-board with respecting other people’s preferred pronouns, for the sake of politeness and mutual respect and conviviality, especially if they make allowances for other people while the rest of us get used to the idea.
(But if I ever catch anyone referring to me as anything other than “xul/xum” behind my back, there may be a price to pay! 
)
I think it’s unlikely that people in more conservative states and communities in the USA would ever refer to the OED to refine their speech while crafting their utterances. However, in the South it used to be that people would say “y’all” for second-person plural.
I wonder if the OP had considered that people in more conservative Chinese-speaking regions and communities in SE Asia might be resistant to a similar request to modify their language?
Also, when it comes to Chinese (Zhong-wen or Han-yu), when would it ever be difficult to distinguish between “ta1” (singular) and “ta1-men” (plural)?
Speaking as a patchy language learner since my teens, hasn’t it always been the case that sometimes the interpretation of sounds or symbols might require a little pause for thought or consideration of either the context or intention, or both?
It could even be considered quite a source of wonderment that humans can even communicate at all in our variety of languages, which are quite a step up in complexity from the sounds that cats and dogs make to express themselves.
It might cheer the OP and other non-binary Chinese learners that in some of the less conservative cities in SE Asia, recently there has been a proposal for a fourth written variation of “ta1”: