Tyrant's Familiar is a house. You should definitely add it in. Scion is still the commander when transformed so it triggers itself.
Also, Hellkite Overlord! Scion was my first EDH deck and I've been playing it since 2012. I'm confident I've turned Scion into this monstrosity more times than any other dragon.
Also, Hellkite Overlord! Scion was my first EDH deck and I've been playing it since 2012. I'm confident I've turned Scion into this monstrosity more times than any other dragon.