I'm from brazil and the biggest issue I see is not the is not the association with this lula:
But with this Lula (former president):
His face is the first thing that comes to mind when I think about "Lula". But, if you don't have contact with a lot of brazilians or don't care what they think, I don't think you'll have an issue. If you do care, but like the sound of Lula, how about Luna, Luana or Lua?