If Ladislaus' birth is butterflied Elizabeth of Luxembourg will marry the heir of Jogaila, Wladyslaw of Varna..as second husband.
Why? She's already 31yo, with two daughters. Menopause started a lot earlier than nowadays (in the 17th century), which means that it's safe to assume that it probably started still earlier than in the 17th (~35yo) in the 15th. Wouldn't it just be simpler to marry her eldest daughter to Wladyslaw of Varna or his brother?