I'm glad to see your post. You're facing the same issue we're facing at our organization. Microsoft is taking the position that if you don't have SA, you do not have the right to run SQL 2016 in a failover role, even though your original license for SQL 2008 included that right, and you've paid for SA which gave you the "upgrades." I don't think it's a correct, fair, ethical, wise, or even legal position on Microsoft's part, and am prepared to challenge it. Please read my post on this forum from just two days ago with the subject line 'Microsoft requirement to have SA in order to have failover server'.