in the next version of the board, I am moving the NeoPixel to behind the nipple, so it really becomes a "back light" rather than an "under light"... :-D
The tubes need socketing with pins in any case, and it's just a question of how deep you want to place the pins. I have made the holes for the pins smaller now, so that people don't get the idea to try and solder the tube directly on to the board. If you have any good ideas or want to get involved with it, I'm tending more and more towards open sourcing also the hardware design. I could add you in any case to the repo even before I finally make that decision.
The USB connector on the VFD board is for power. The others still need >5V on the power input to reach the required voltage. Remember those little transformers I sent you? Those were meant to be part of the solution to my HV problems so that also Nixie boards can run off just a USB power input. It went quite a bit down the list just at the moment.