Sina (aka. Sinā) is basically to Chinese people what Nida is to Koreans. Sometimes Sina and Nida team up to cause mischief together.
He wears Quing Dynasty drip and ends all his sentences with "アル"/"aru".
As you can see from this data, Sina is clearly not a trustworthy character. This is probably to be expected because he is a racial caricature and shouldn't be expected to act like an accurate representation of what real Chinese people are like, and also because he has an incredibly villanous looking mustache.
At least now we can be certian that Sina is not the imposter, as he is able to sucessfully complete scans in the medbay.
Wana (aka. Wanā) is a Taiwanese version of Sina. He is friendlier than Sina and runs a bar where he sells Taiwan Beer.
He wears aboriginal drip and ends all his sentences with "ワナー"/"wana".
