I love Henry, Isaac, Jesse, and Rosalie! I'd pronounce Mattias as Muh-TYE-uhs. I much prefer Matthias, tbh. Sorry!
Never been a big fan of boys names on girls, though I do love Spencer for girls. Wyatt is not a name I like on either gender. Elliot I like solely on boys. I think if you balanced them with a nice, girly choice they could be nice. Rosalie Wyatt would be really pretty.
You have a really nice overall list!
I'll make some combos for you.
Ladies first:
Rosalie Wyatt
Darla Snow
Leah Elliot
And then the gentlemen:
Isaac Fallon
Henry Mattias
Jesse Dexter
Suggestions from outside your list:
Veronica Snow
Elodie Wyatt
Emmeline Darla
Hadassah Snow
Rosalie Haven
Isabella Wyatt
Gwendolen Snow
Caroline Darla
Snow Evangeline
Rosalie Memphis
Madeline Elliot
Darla Jolie
Dexter Caleb
Seth Mattias
Isaac Leo
Mattias Archer
Jesse Orion
Henry Silas
Dexter Sebastian
Isaac Emory
Fallon Brady
Dexter Noah
Jesse Cannon
Isaac Montgomery