I like
Phineas in theory, in practice, I find the association with
Phineas and Ferb too strong.
Cillian is not my cup of tea, mostly due to the "kill" sound.
Phineas "
Finn" is alright.
masculine list:
https://www.behindthename.com/pnl/191050/124079feminine list:
https://www.behindthename.com/pnl/191050/124080