Oh yay!! I love Mattea. I've liked Taya for a while and when friends named their son
Matteo a year and a half ago, I discovered Mattea and it's been number one ever since. My husband was a little reluctant at first, but it is now our top girl's name, should we ever need one. I love all the nicknames your mentioned and I think that most people would guess the right pronunciation (or quickly learn it once told).
I love
Amelia, so Mattea
Emilia caught my eye, but I think the endings are a little too similar. My favourite MAttea combos right now:
Mattea
GabrielleMattea
JuneMattea
Bryn
Great name!