You mean like this?:
yPos = 0 - font.getGlyph('A', fontSize, false).bounds.top;
This seems to work for me; it places the "l", which is one of the longest characters, at the y-position it's supposed to.
With "getLocalBounds().top", I do it like this:
tempSprite.setPosition(xPos + font.getGlyph(str[i], fontSize, false).bounds.left, yPos + font.getGlyph(str[i], fontSize, false).bounds.top - tempSprite.getLocalBounds().top);
Yet it does absolutely nothing.
Well, I guess it doesn't matter, since I seem to have fixed everything.