All of your logic must be 3.3V. This means RS, WR, CS, RESET, ... as well as the data pins.
I suppose that you have got enough pins but you lose the Serial pins.
I doubt if anyone has ever written a driver that expects to have 16-bit data bus on 16 random pins.
Yes, if you provide the software, fix the hardware, keep your fingers crossed, ... it should work.
There are Uno Adapter shields that will drive a 16-bit data bus (and do the level shifting)
They have an 8-bit latch, and require special software to drive it.
Life is much simpler if you buy a MEGA Adapter Shield. Or if you just buy a TFT shield that is designed for a Uno in the first place (no adapter necessary)
David.