Personally I think they need to do more non-human options that are not "Classic fantasy races in space" after the Damned get done in plastic and this idea is not out of line with accomplishing that.
Maybe instead of just a mystery science team, make them an alien exploratory force/science corp/science expedition, with the backstory that they are an "unbacked team" that is actually in the circuit by accident because they are lost: Thier navigational computer is dead, they don't speak any of the known "true civilization" languages so they can't ask for directions, and they have a horrible sense of direction that is equal to Ryoga Hibiki’s epic inability to get from point A to point B😆. Yeah, really lost in space🤣.
Of course the original "humie science team" idea you had could honestly be done as a non-Death Fields set and the start of a new SciFi line more believably lore wise, which would not be a bad idea. Frankly Death Fields is more "Battle tournaments in space" than good adventure SciFi which is a pretty big niche now thanks to starfinder and Stargrave (not to mention all the other SciFi TTRPGs), plus if done in WA's non Death Field normal "historical scale" it would work great with the Iron Core sets and other historical scale sets for time travel nonsense and probably get more of the parts you want on the sprue with less sacrifice to the number of bodies (less chunky proportions equals more stuff on the sprue).
It doesn't seem like the kind of thing that will sell in large numbers, which a hard plastic kit needs to do. Definitely a more niche product, better suited to 3d prints or potentially metal. Off of the top of my head I can think of a few things that are already close-ish to what you describe, and the Cannon Fodder could make for a reasonable approximation, barring some of the more fanciful weapons you describe.
https://bombshellminis.com/gcw/
https://www.battleprints.co.uk/products/space-dwarf-exo-dwarves-x-3-federation-of-tyr
https://mustcontainminis.com/2021/03/american-power-armour-by-gaddis-gaming.html
aside from the retro-scifi weapons, you could get fairly close by putting cannonfodder spacesuit heads onto the Eisenkern armors.
I wonder if this could be made to work commercially with a stronger visual identity. Fallout Wasteland Warfare seems to sell, so there seems to be a market for that kind of 1950's American retro-futurist aesthetic with hints of pulp sci-fi thrown-in. You mention diving suits, which reminds me of the Big Daddies from Bioshock, although they were typically armed with industrial equipment, like large drills or rivet-guns, be visually were of that same era.
I think this could become something that could reasonably stand-in for something like Mantic's Veer Myn (drills and rayguns) or some kind of wierd-war/alternative history pulp-scifi, but I'm still dubious about the breadth of such a kit's appeal. It also doesn't fit into the DF theme of historical armies transported to a sci-fi setting. Generally the DF kits work as historical or moderns in heroic 28mm scale if you leave out the overtly sci-fi weapons.
Alternatively, this could make good fodder for another weapon/upgrade sprue. I don't know how well the previous one sold, but if another is on the cards then perhaps pulp sci-fi weapons and heads that could be thrown at a variety of other kits would work well enough to get into production, and allow you to create the army you describe with bodies from elsewhere?
