That's an interesting question, Uncle Roger. Given that RH debuted on July 7, 1975 and
Alien Lover was shown on November 25, 1975, either case is possible because who knows how long AL was shot before it was shown? It could have been months - it could have been weeks. Though I might lean more toward KM being cast because she was already part of the ABC family and had already begun working with LS...
As for AL itself, I'm sure I saw it back in the day but I have no recollection of it. And I'm a huge KM fan. So, I look forward to revisiting it. Thanks for the link, Gothick.