I also heard a HUD mentioned in one of the interviews with Lucid personnel, but nothing since. In fact, another Lucid staff member mentioned that the combination of the squircle and the raised Glass Cockpit put all the relevant information in the driver's line of sight -- a point I took to imply that a HUD would be superfluous. I've driven a couple of cars with HUDs, and the only feature that ever appealed to me was the overlay on NAV directional signals on the actual turns ahead. But for that feature not to be more confusing than helpful, you'd have to be using more precise mapping than HERE currently offers.
P.S. I did not get an autocorrect alert when I typed "squircle". I guess that term has taken root in our vocabulary . . . sigh. I just hope when I finally try it, I don't feel compelled to name it a "squeel". (We're getting the yoke on our Model S swapped for a wheel on the 18th, at which point I might not mind occasionally driving that car again.)