I live in an English-speaking country and I've never heard of a male named
Gillian. I currently work with a female
Jillian, that spelling, an alternate spelling that is fairly popular. I've never heard that it can be a male name.
I pronounce it with a soft G. I've never heard it pronounced with a hard G. Not sure if it would depend upon the region. I've lived in many different regions of the US and never heard it pronounced with a hard G.