level 5 is to expensive for the beginning, actuall i would go for level 4 as a newbie ... Maybe even a level 3 coach for one or two thoousand Dollars could help during the offseason.
What training is good at the beginning is more difficult, you could say stamina will improve your team because a lot of player have pretty weak stamina* but i would also say you would be pretty happy when you got more then 3 players who are worth to get training so i would go for one or two position training and buy better players from time to time for your rooster and don't invest training in the start team.
* i'm playing still with players with weak stamina, and the effect ain't that high ... i prefer FreeThrow training instead of then, which is usefull especially in the low skills betwenn one and 3(atrocious till inept(??))