It should be girl's soccer team ;)
Yes, girls can be on a boys soccer team even though there is a girls team already.It really doesn't matter.
Any girl, girls special soccer teams exist.
Boys soccer team. I think. No, it should be boys' soccer team. Just like you would put "children's soccer team", you need to create the plural, and then add "apostrophe s". In this case, leave off the "s" because "boys" ends in an "s".
You probably need a possessive: girls' soccer team (the team that belongs to the girls, the team they are part of). But don't be shocked if you see it without the apostrophe-- sometimes people just write it the way you did, even though it should have the apostrophe.
It depends on what style you are writing in. Typical AP format dictates that a soccer team of females is known as Girls' Soccer. I could be wrong on this one, but I think MLA format rules contrarily. In MLA, I do believe it is Girl's Soccer. Good luck.
diamonds
Nigeria
Yes.
The Orlando Pride.
yes
Yes, they can.