help creating sibset

Trying to Create a sib set of

Boy
Girl
Twin Girl/Boy
Boy

So far I have names of the last three, but can’t think of any names that fit the set for the first two.

?
?
[name_f]Lilly[/name_f] and [name_m]Quill[/name_m]
[name_u]Flynn[/name_u]

Would prefer short, maybe one or two syllable name suggestions for older siblings to Lily, Quill, and Flynn.