We just found out our twins are girls, so we've narrowed down the list. Which combo (or other configuration) is your favourite? Gray, Aline, Rose, and Eve are all family names, and our last name is a one-syllable Y name.
I think your first pair are absolutely gorgeous and unimproveable. Only disadvantage I can think of is the most obvious nicknames of both have similar sounds for shouting-across-the-park purposes (Fliss and Viv).
You could subsitute "Rose" or "Aline" for "Winter" so that both have family middle names, but then Winter is so beautiful.