I don't think
Luca sounds feminine at all. To me, it sounds like a nice Italian boy's name.
Using
Luke as a nickname for
Luca is do-able, however it doesn't sit right with me. It's like using the nickname
Kate for a
Catherine. For
Luca, I think
Luc would look better, but it's about personal preferences. :)
As for middle names, I once favoured
Luca Olivier after the brilliant actor. I'm not so sure of your style of names, so I can't give an opinion at the moment.
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