I
definitely support Hatti's return and I've got so much to say and so little time.

>
Suppiluliuma is my prefered leader choice, but I quite like OP's Queen idea
> Hittites were renowned for their
metallurgy and their abilities should reflect that (science from mines, start with vision of iron, coal, aluminum & uranium, etc)
> The Hittites also signed the
first ever peace treaty, so a diplomatic ability isn't out of the question
> Hittites were foremost expansionists. A
Chariot UU is excellent, since three-man-chariots is what they were famous for. The name "three man chariot" itself is meh, though.
Meshedi were the bodyguards of the King, so maybe use that as a name instead.
> A UA which gives them
bonuses towards City State Conquest is a pretty true-to-history ability for them. There are other options, if the combat system is further deepened to include
morale or
war score.
Also, I'm working on my own Civ7 vision (which I plan on presenting when I find time/once its done. July at it's earliest). This is my current prototype of what a Hittite city banner could look like:
Dark Orange and
Yellow would suit them nicely since their most famous symbol is a sun disk and orange is generally a difficult colour to assign (other than Netherlands and maybe India). An alternative could be a shade of
pink to symbolize the
dawn [of a new era in which the Hittites will crush you with their chariot spam]