Ran across this today, an edit someone made of that user's tweet.
Which leads me into another point continuing what I said before.
If the thinking of "only one can occupy this space" still applied today, you would mostly see fans fighting with each other about who counts as Magneto's kid. But that's not what we see. What we see is fans wanting the whole family together, annoyed by Marvel keeping them apart. They don't just want the twins or Lorna to interact with Magneto. They want to see the siblings spend time together too. Not much needs to be said on Wanda and Pietro as they've been a pair from inception. With Lorna, they wanna see her and Wanda form a badass female fighting sister duo. They wanna see Lorna and Pietro snark each other and be playfully combative, which Peter David did well. There's a Tumblr account called Keeping Up With The Magnus Family with fun posts like this:
Of course, this kinda stuff wouldn't happen in Marvel's comics (as it doesn't really fit the 616 versions of them), but it shows how much power and interest the family as a whole has among fans.Erik: what do you guys say when you answer the phone?
Wanda: hello?
Lorna: who the fuck is this?
Pietro: oh no he’s in jail this is his son.
And now I'm imagining them as a mutant version of the Fantastic Four.