I think a prequel to the FaS/LaD story would be the easiest to realize.
You could even have it be set on earth without aliens to save on the cash.
Before his obsession with the engineers Ahab probably went after humans at some point of his long life, so he knows about earth and its inhabitants.
Your suit has the face damage already, so he roughly knows about the engineers by that point, but he has to spend his time somehow until he got more clues on them.
Maybe have him search for engineer traces on earth. He found them on the four armed humanoids planet, maybe he made the connection that there are also traces on other humanoid's planets, like earth.
There he could run into trouble. Maybe have him search places of ancient civilizations for clues. This leads him into some crisis area where some armed militia/terrorists/goons try their luck with illegal excavation to fund their cause. This way you could use a mix of dated equipment\weapons/uniforms, again doing some saving on coin.
Sure Ahab vs militia does not sound very fancy or big scale/epic, but I think it would be more doable than something in space with aliens, colonial marines, engineers and all that.