Welcome the game johnsickels. You can learn a ton of info from deep diving the forums and watching the TTATO content and tutorials. So you're at the right place :)
As for being able to see your team's previous rosters - that option isn't available to my knowledge.
HOWEVER, to see your team's season ending stats for and against follow this path:
When you're on your team's main page click your team name in the banner at the top of the page, an info page pops up and you'll know you're at the right place when you see the tabs ROSTER, RATINGS, FORMATIONS, STATS, GAME LOG, etc.
Click on the HISTORY tab an the tab opens to display MOST WINS, MOST SEASON, MOST CHAMPIONSHIPS in the first section of that history tab.
The second section shows SEASON, COACH, OVERALL WL, CONF WL, HOME WL, etc. This info is ordered by most reason COMPLETED season.
Between the first and second section is a drop down menu box labeled TYPE. Click the drop down arrow and you can change that default general info to STATS FOR, STATS AGAINST, and NFL DRAFT.
That's a close to meeting your request as I can figure. GL and if you have trouble follow these directions lemme know.