Multiple players on offense form "wall" to screen for shooter?

[NoFussRef]

***Sitch.1***

AAAA 8th grade boys. (NHFS with some youth mods.)

Team A is inbounding in FC from baseline. They line up 3 of their players shoulder-to-shoulder (even wrap their arms around each-others waists) about 1ft inside of the 3pt arc. Team A then inbounds the ball to a cutter going behind the "wall" who then attempts a 3pt shot.

Legal?

Similar enough to the above question:
***Sitch.2***

6th grade girls. Rec-ball (still learning to walk and chew gum stage :> )

A1 enters FC and begins drive while guarded by B1.

Now this is where it gets interesting....
ALL 3 of A2,A3, and A4 come up and set a screen on B1 in what I can only describe as a triangle formation AROUND B1. (Man defense only in their league, no backcourt guarding allowed etc... again walk/chew gum).

Unable to cite any rule/case for why this MUST be illegal I explained to Coach-A that her tactics seemed to take away from the purpose of their league which is to teach fundamentals and help players improve.

Thoughts or actual rule/case(s) we could apply to either of these situations?