When I hear "Halliet" I think that it's someone with a stong (fake?) Chinese accent saying Harriet. So to me it sounds made-up and rude. Harriet's a gorgeous name, no need to change it!
Ditto.

But I don't get why you couldn't use it?

Harriet is number 2 on my list for this baby. So, umm, more names, JF, just for the fun of it!