The previous exercise that I was given gave "fun" as a suggested translation for "zabawny". I tried "fun" with this exercise and was marked wrong (Duolingo is wonderful, but of course, there are limitations to the level of consistency that is reasonably achievable).
Are there contexts where "zabawny" would be translated as "fun"? Does it very closely correlate with the English word "funny"?
Edit: The other exercise was Write this in English -- "Jesteś bardzo zabawny!"
No, it's the not masculine personal plural. While on one hand it would make sense for it to be masculine personal (there easily can be at least one boy among your children), it is plural of the word "dziecko", which is neuter.
So if there were only boys in the group and no girls, would we still say twoje dzieci and not twoi dzieci? Russian doesn't have this construction, so it's a little confusing.
Yes. The pronoun changes with the noun, the noun can change according to the gender of described people, if there are two versions of course. So you can have "przyjaciele", which will be "twoi", and you can have "przyjaciółki" for girls-only, which will be "twoje". But I don't believe there's a word which could take either version of the pronoun. "Dzieci" just have one form, so it will always take "twoje" despite their gender.
Just like "rodzice" will always be masculine plural, even if we write about a country which allows same-sex marriage and therefore can have 'parents' = 'two mothers'.