Guys, I did it. I found the answer to the nearly impossible question.

Let me explain...

I was randomly Googling my OTP and found this picture that made me come to a startling conclusion:

Bianca: picked the archers over Nico.

Hazel: picked the archer over Leo.

Nico: picked the archer over Percy.

...They all have one type-archers.

THIS IS ROCKING MY WORLD

Now we know Nico's type!