On Leader and Clerk Resources, under Organizations > Full-Time Missionaries, you can see a report of all the current missionaries serving from your stake (or ward, for ward leaders). However, the email address listed for each of them is only as good as what's been entered in by the ward clerks. I would encourage the ward clerks in each ward to update the email addresses, or the parents of each missionary to update their son/daughter's email address.
To improve the workflow in the future, perhaps this could be done by the missionary himself or his parents when he comes to the stake president to get set apart as a missionary. And it would be helpful to follow up with the missionary after the mission to make sure their email address and phone number are updated again after they return home.
Samuel Bradshaw • If you desire to serve God, you are called to the work.