I find it a little odd that Irelia is on your list here, when her weapons are far from conventional.
(on top of that, story-wise, remaking Irelia would probably be a liability for PROJECT, so, I'm not 100% sure they'd go for it.)
A couple other candidates that I could think of off-hand;

Although I'd also discount Pyke from the list since he just got a Blood Moon skin to start off 2019.
While one could argue that Forsaken Jayce is suitably futuristic enough to prevent him getting a PROJECT skin, I think that, alongside Braum, there's some interesting opportunities to add more to the PROJECT: universe.
And, if we're counting other Champions who already have futuristic skins (I mean, we've got Sivir with Pax Sivir, I've added Jayce with Forsaken Jayce and Kayn with Odyssey Kayn, and one could also argue about Crimson Elite Talon, amongst a few other skins), I'd probably also add a few other notable candidates:

Despite having Pulsefire skins (which look very much like the sleek visual thematic of PROJECT:), Ezreal and Riven are still both solid candidates for PROJECT - Ezreal especially, since his gauntlet makes for an interesting piece to his model. Riven, of course, has been a fan-favorite idea for the PROJECT skinline since it started with Yasuo.
Graves, despite having his Praetorian Skin, would also make for a seriously interesting addition to the PROJECT roster. And, Viktor, who already has Creator and Full Machine, would also be somewhat interesting to see given new life in the PROJECT universe - arguably more for story reasons than for visual ones.