Hard to say what's up post retcons since it's not even clear if Marvel remembers about either Magda or Miss America at this point, but since the only common connection seems to be High Evolutionary, then the name must've come from there, but and maybe either Miss America or Magda came up with 'em, or maybe Marya did, or Natalya did, or I dunno, Bova came up with them lol.
They might've died like the rest of the twins, but it's unknown at this point lol.
So, in order:
Giant Size Avengers#1, Whizzer and Miss America were Wanda's and Pietro's parents.
Avengers#186, it's actually this woman named Magda, and she went to Wundagore to to give birth to her kids in secret because of Magneto, and after she gave birth, she left the place to die so Magneto can never find the children, then, Whizzer and Miss America went to Wundagore, Miss America gave birth to twins, who died, and then Bova offered Magda's twins to Whizzer, but the death of his wife made him run away.
It's not clear if Bova told Whizzer if the babies were someone else's children or not, but considering that in Avengers#186, she only points out that he ran away because of the death of his wife, she probably didn't tell him.
Now, Uncanny Avengers#4 vol 2, High Evolutionary says he kidnapped Django's and Marya's children, made some experiments on them, considered them a failure and dumped them back to the family he stole them from.
How do Miss America and Magda fit into this? Who cares? At this point Marvel certainly doesn't.
Now, Scarlet Witch vol 2#11 reveals that Natalya gave birth to twins, and left them with Marya, and High Evolutionary wanted those twins, and eventually got them:
https://i.imgur.com/TIrpDrD.png
So, if we try to make a timeline out of this, Natalya gave birth, left her twins with Marya (Scarlet Witch#11 vol 2), High Evolutionary kidnapped them and made experiments on them (Uncanny Avengers#4 vol 2), then at some point during this, Magda shows up in Wundagore, gives birth to twins and leaves (Avengers#186), then, Miss American and Whizzer show up in Wundagore, she gives birth to twins, she dies and so do the twins (Giant Size Avengers#1 and Avengers#186, but with Avengers#186's retcons), then, after all of this gives Wanda and Pietro twins to Django and Maria (All versions), because the experiments he made on them were failures (Uncanny Avengers#4 vol 2).
The most blatant plot holes here are related to Magda, since she's not Pietro's and Wanda's mother anymore, then stuff like when Wanda was born there, from Magda, and a mysterious light shined when it happened, can't have happened, and the set of twins from Magda just, disappeared lol.
Also would be funny if Marvel remembers this detail, decides to say Magda's twins are alive somewhere, just so Magneto can have more children lol.
But, as y'all can see, it's very easy to follow :P.
Kinda funny that as bad as all of this is, it's not nearly as bad as Donna, and thankfully, unlike Donna, we don't get too much focus on Wanda's past, likely, or hopefully, she won't become Marvel's Donna.