How do I know to use Ei and not Ele?
ei = they masculine
ele = they feminine
In that case, would it be the same as in French, where if 'they' refers to all girls it's 'Ele' but if 'they' refers to a group with one or more boys in it it's 'Ei'???
yes it is
What is the right pronoun when "they" includes feminine and masculine?
As I know, the masculine pronoun is used even if there is only one man among lots of women!
Just like french, if there are a million women in a stadium and one man it's Il instead of Elle.
Yes, unless there's a man among them (or several) it would be Ele
Is "Ele nu sunt copii." correct? I mean when we're talking about a group of women.
Gender agreement requires feminine plural "copile".