I had an idea for this name but I do not know if it would come across as guy's name or girls, for an example I wanted to use the name Blair, but should it be Blaire or just blair? Blair for guy or Blaire for girl. or if used the name Bobbie as girls name would readers think it's a guy?
I would spell Bobbie if it were a girl and Bobby for a boy. I have come across a Jody spelt the same way for both sexes.
Life is not a rehearsal!! Blair would work fine for a guy, even in the USA. Blair Walsh is the quarterback for Minnesota Vikings. I've known both male and females named Blair or Blaire. I believe I've actually known more males with that name.
Bobby for male
Bobbie for female
For a girl's name should it matter if it is masculine? I don't think so, if the title is catchy people will read regardless.
When I use unisex names, I make sure to check spellings as more often than not the spellings differ between male and female. I also, like Burquette said, set up the gender of the character as much as I can, so the reader knows that, despite the unisex name, the character is male or female.