Different leagues have different methods for determining allstar teams and coaches. A very popular method for determining an allstar team is voting by the coaches and league commisioner. Usually but not always the coach of the team that won the league will be the coach of the allstar team.
The exact value of a 1979 Dallas Cowboys football signed by the entire team would actually be dependent upon a number of factors. Some of these factors would be the authenticity of the signatures and the condition of the ball.
It would most defenitly help to know them, and i would say to be on a school cheerleading squad you probably would but for a Allstar squad you probably wouldn't but it would help. Most Allstar teams accept anyone who wants to cheer
if its for a school team then teachers and faculty from the school usually volunteer to sponsor the team . but allstar teams dont usually have sponsors , they only have certified coaches that now technique and are familiar with safety. hope i helped ! (: