1) Expect not every kid to be on time, you may be forced to start the individual photos first with some teams and do the team picture in the middle or at the end. Just because the coaches/league say to be there early for the team photo does not mean they will, and yes coaches will ask you to wait. Happens ALL the time in the league I shoot and rather have all present so gladly oblige.
2) The sun is going to change so you just have to keep up with it and adjust your settings on the fly, ALWAYS shoot T&I in RAW if at all possible because of this. I used to do JPG but have since switched and honestly smack myself for not going this current route earlier.
3) Expect changes in direction, i.e. backgrounds, depending on how long you plan on going. I did one shoot that started at 9am and the last team went at 3pm - we were facing almost completely opposite directions by the time that last team came up from the first. Luckily had planned for that so the background was clean throughout, hopefully can find an area you can move around a bit.
4) Ditch the tri-pod and remote, you're dealing with an age that differs greatly on size so having it on a tripod means a lot of adjusting. If possible have an assistant that can help with the posing (I offer 3-4 poses usually but having one will be the simplest), you're not going to be shooting at 1/40 f/22 I'd hope so should have plenty of shutter to hand hold.
5) Personally I use studio strobes for both, team and individual, just changing them around depending what we're doing, very easy to go back and forth. If doing so make sure you have something to hold them suckers down, I have a destroyed strobe or two that says even the smallest wind can knock them over pretty quickly. Hell, even one was held down by sandbags and still got picked up by the wind and slammed to the ground. Destroyed one last week with a breeze I didn't even feel but the kid holding it walked away (thanks bud!)
6) Have a little fun with the kids, it's a great age to shoot and always interesting!! Thought I'd hate doing T&I but immediately was one of my favorite things to do each year with the local league after they finally talked me into doing it, only took them four years to do that and wish I started sooner.