First of all, sorry I replied so late, but this is my first time seeing this post. Secondly, it only lets me put up seven photos, so I am going to have to double post to show you the rest.
Here are some images I think might help.
Here is the main menu.
This is the screen right before a match.
This just shows what each stat stands for when you look at a team.
This is a pitching menu. Specific pitch may vary from what is shown.
This is the pause menu.
There is no disadvantage to using super players. They will eventually run out of super pitches and hits though. Like all pitchers, the super pitcher will get tired after a while.
Since I do not use season mode much, I'm not sure how to trade.
As long as you start season mode after you create your player, and use the team you put your player on, he will be in the lineup or pitching rotation.