Edited for privacy.
I agree that you should just keep [name_m]Zachary[/name_m] in it original form or a slight change to [name_m]Zacharie[/name_m] bc it does look a bit more feminine. Unless you’re Scottish, I suggest definitely not using that spelling. It’s just too distinctively spelled and hard to pronounce with one look at it - “oh my mom gave me this name bc it looks different but it was convenient bc it sounds the same as [name_m]Zachary[/name_m]” - it’s just kind of ghetto fabulous and nobody wants that. 
Zaharina isn’t too bad but it reminds me of a Russian Tsarina. Definitely original or [name_m]Zacharie[/name_m].