Here’s an idea from me, whenever there is a shot similar to this:https://i.imgur.com/Fi0gqkp.png
Put small, just noticeable blobs of blue around the edges of a characters head. Since you’re trying to make this look like something from the 80s this effect will make it more obvious that the actor/s are in front of a blue screen. Empire had a similar problem as seen here: https://i.imgur.com/Ek9Hjej.png
Awesome idea, thanks!