After a survey goes out to the members, how will a member receive it if their email was wrong? Will they get the survey once they update the email address? Or can the survey be sent to specific people who the admin knows have updated the email address?

No. When an email is triggered to be sent, it an email address is incorrect, the email will bounce and flag the account so that no new messages are sent until the member either verifies their email address or corrects the address. Once corrected, we do not resend missed triggered emails. You would need to follow up with that member. You can always copy the link to the survey page and use the email the class function to sent it to specific members.