Can "tineri" be seen as an equivalent to the English noun "youths"?
Yes. Moreover, "youth" is „tineret” (mass noun).
Is it in any way related to "teenager" - or is that just an easy way to remember this word?
If you want to use that as a mnemonic help, it's ok, but the ethymology is from latin tenerus, which means soft, tender, and figuratively delicate as something newborn.
Fairly certain "youngsters" and "young people" are the same thing. Both should be accepted.
why 'youngsters' is not accepted?
YOUTHS should be accepted.
I have a question: why if we translate from Romanian it's "a merge cu doi tineri"; but if we translate from English than it's "a merge ÎMPREUNĂ cu doi tineri"? To translate from English is one of the tasks here
Actually, it would be more accurate to link "tânar" with "tender"
It would be good not to introduce a new word in a listening-only exercise....