The third movies takes place in 1988. The third movie is actually the first movie. It goes back to when the characters from the first 2 were little kids. So no, you don't need to see the second one before watching the third.

no you will be able to understand it just fine as the two children are from the 1st 2 as well but as adults because they have done the films backwards for some strange reason (another words the 3rd is technically the 1st, the 2nd is the 2nd and then 1st one is technically the 3rd films), its weird how they have done it

Technically no, seeing how its a prequel to 2, lol I wouldn't hurt if u haven't seen it. Its ok to see it later

I never watch the first or second. I understood the movie just fine. So your answer is no it doesnt matter.