On the first case each team will play in a different league. If we number the kids from 0 to 9:
Team A: 0-1-2-3-4 Team B: 5-6-7-8-9 (situation 1)
is different from
Team A: 5-6-7-8-9 Team B: 0-1-2-3-4 (situation 2)
Because the teams will play in different leagues. Imagine you were the kid 9. It would matter to you whether you play on Team A that goes to Division1 or Team B that goes to Division2.
On the second question you have kids on a playground ready to play a basketball game, situation 1 and situation 2 are exactly the same. The composition of the teams is equal on both situations and for a kid it's equal to play on Team A or Team B.