Colour me interested - though considering the dating/timeline I'm not 100% which of my warbands I would use for this, in relation to the character backgrounds for them.
One issue is that the leader of the one I'd use if I painted them up in time is Inquisitor Jack Jomar (middle to late in his career) carrying both Bolt pistol and Power Sword (intended to be a mark of how much influence he has gathered over the decades), and backed up by three others (one with a sword and some daggers (assassin conversion), one with a pistol and handbow (barbaretta conversion), and one with shock baton and plasma gun (heavy conversion using judge, guardsman, and covenant parts, with an SM plasma cannon converted to look like a bespoke/older model plasmagun). That would - (by my rough envisaged timeline) be appropriate to the timeline of this event.
Alternately, Helena (my orechiel model with minor conversion for the pistol into a bolt pistol - normal sword only, but she's psychic) could turn up with my thieving Rogue Trader (he likes to steal your flying vehicles), which would also fit.
Then there's my standalone 54mm version of my 28mm Inquisitor who currently hasn't got anyone to go to the party with (though I have a vague idea that might change that). Trouble is, he wields (much like the 28mm Gideon Lorr model he's based on) a plasma pistol and power fist. No backup weapons though, and not a lot in the way of armour - flak maybe at most.
Of course, the backup for him would be his rather puritanical acolyte, when she's dressed up in some power armour, with a bolt pistol and her trusty hammer (though I'm thinking of forcing her to wield her laspistol instead at 54mm scale, just to tone her back a bit). But that'll take some conversion work to find a suitable one-handed hammer, plus fashion her hood and braid onto the model (based on the daemon huntress of course - wonderful model for a sister of battle, really).
I'll admit I'm sort of tempted to have the Inquisitor travel alone, just to balance it out. But he sort of seems (when I look at him as a character) to almost need at least one other model to back him up.
The other warband would be Interrogator Jack Jomar (rather early in his career) and the Inquisitor who trained him - the only high end weapon here is a plasma pistol, backed up by swords, shotguns, pistols, etc and nothing very strong outside of that. Could be explained by warp related time travel shenanigans, or similar, only two models, possibly some theft of flying vehicles still, but I'm not entirely sure it would fit in with the story if I explained it that way.
I've got a squad of three enforcers (two barbaretta models, one with open helm, and one judge model), but I don't think I'd play those as prime characters - more likely to be NPCs.
After that, there's my 28mm band (bands? still not decided yet), but outside of my Lorr model, I don't have 54mm versions.