As the coach, you can send a team email from the team page and it will go to the primary, secondary and participant email.
From Home page click Team Central >> Team Directory >> Email
Then select the players / coaches you want to email.
Rosters
Click Team Directory, find your team, click team roster, right next to the option to switch between roster view or photo view, there is a pic of a printer and a button that says Print Roster. When you click on this, it brings up the extended roster for your team. This would include secondary email addresses they may have entered during registration as well as parent cell.