All three of them work. "those" is perhaps the most awkward. But in reality, the way the sentence is written to begin with is a little strange for a native English speaker. It sounds like you're trying to be dramatic and the subject doesn't call for it.
A typical English speaker would probably say "Are the words till and until different?" and wouldn't use a pronoun at all.
As for your question, yes mean the same thing: https://www.grammarly.com/blog/until-till-til/