Myles/Miles - Like, prefer the spelling Miles.
Dylan - Don't like.
Zach - Don't like.
Isaac - Don't like (but you could always use this with the shortening Zach).
Christopher (kit) - Love Christopher, but not a fan of Kit.
Felix - Like.
Hugo - Like.
Sebastian - Love.
Gabriel - Don't like. Too religious for me.
Theo - Like, but prefer it as a shortening for Theodore.
Lysander - Don't like. Very different from the rest of your list. Would look pretentious on 9/10 boys.
Finn/Finley/flynn - Love Flynn, lukewarm on the others.
Oscar - Love.
Toby - Like.
Orlando - See Lysander. Will also only remind people of two things automatically: 1) Florida and 2) Bloom.
Violet - Love.
Indigo/Indianna - Don't like.
Alexa/alexis/alexia - Don't like.
Phoebe - Love.
Isadora - Not a fan. Prefer Isabella.
Mariella - Not a fan.
Seraphina - Love.
Seren - Like this a lot, but you could have Seraphina nn Sera which is somewhat similar.
Clara - Like this.
Ivy - Like this, but very "now". I know loads of Ivys born in the last 3 years.
Jasmine - Don't like.
Isla - Don't like.
Matilda - Love.