Our answer when it came to Sims was exactly the same answer. You have to enter Create-a-Household every time you start a new file. Saving to the bin means the Sim Bin not the Household bin. You cannot use Move In Household ever in a challenge. You must always enter CAS at the start of each file.
Actually, no it's not. He said, and I quote, from the previous quote I quoted, "the save to bin option is fine", and mentioned that Pam sometimes does this. If this has changed, that's fine, but it's not what he said above, and it's also not how he's replied to an identical PM question in the past, and that's why I asked for the clarification in the first place.
My game only has one bin, the household bin, which is where all sims I create in CAS are automatically put when I create them. Move in household takes from that bin. In fact, if I create the sims first and then edit the town, I must use "move in household" to start my game -- and that's often the order I do things in. I'm not discussing the clipboard at all -- that only takes sims that have already seen game play, and of course would not be allowed.
And, thank you for the other answers! I appreciate it!