I love this thread so much, I could cry.
Lots of good ideas, especially the sea plane vendetta conversion. I imagine that there would be a fair amount of aircraft used on a water world.
As for the guardsmen themselves, I like the idea of having the chimeras be their landers/beach crawlers. The port-holes is a good start (don't know how you'd do realistic glass, though), but I think what would REALLY sell it is if you had your chimeras encrusted in naval paraphernalia. I'm talking about every vehicle having:
Self-explainatory
Grapple gun launcher, perhaps based off of a regular missile launcher with some plasticard, perhaps counts-as
HK
A collapsed life raft, rather than an open one, of course.
Both rope and extra toggles. You've got to dock the chimeras somehow.
Some netting that hangs off the side. This could easily be achieved with some screen door material painted rope color.
Plus perhaps some life jackets, an anchor, perhaps a small bouy. If you wanted to go real crazy, you could start using a tiny bit of
GS to quick throw some barnacles on.
This would be SUCH a cool project to work on.
Anyways, as for the guardsmen themselves, I'd try and stick to a single thing that sort of makes them look aquatic. Tanks have tons of room for detail, while smaller models will quickly look cluttered. Whether you wanted something big (they all wear life jackets), or something small (a bunch of extra equipment and not a backpack), I'd stick to just one kind of theme.