What a load of BS. They’re straight up lying at this point. Regina is not in all the flashbacks in 7×02. She’s probably in one or two of the scenes.
Let’s not forget the fact that JMO filmed all her stuff for episode 2 and Lana was in LA during that entire time. Adam has also stated that JMO is in a lot of the episode. All of Emma’s stuff is obviously flashback, so that says it right there. Regina is not in 7×02 flashbacks for a majority of it. Unless she filmed with Emma via green screen or stand in.