I do remember those old Renwall kits. The Compass Island was one of the stranger plastic ship kit subjects - a "navigational research ship" used in the fifties for, if I remember correctly, testing new radar systems, LORAN, and other fancy electronic navigation equipment. (No missiles; perhaps the guided missile ship honneamise is thinking of was the Revell Norton Sound, which was a converted seaplane tender. Revell Germany recently re-released it, in its later guise as the U.S.S. Currituck.) The Seminole was a reasonably accurate model of a standard U.S. Navy attack cargo ship from the WWII period.
Attack transport kits were particularly important around our household when I was a kid, because my father had been an officer on board one of them (U.S.S. Bollinger, APA 234) during the war. The Renwall Sarasota was indeed a full-hull model of a Haskell-class attack transport, and in some ways it was indeed a little superior to the Revell kit. (They had nothing in common; the Revell one was bigger.) I don't know how many times my older brother and I built both of them (along with Lindberg's LCVP).
Renwall warship kits in general were on a somewhat more sophisticated level than most of the competition of the time. They had individual 20mm guns (not great, but better than the integrally-cast blobs on the Revell kits), and a special feature called the "No-Show Cement" system. The bottom of the hull had a big hole in it; the modeler was supposed to insert the pins on the bases of the various detail parts (including the 20mm guns) into the deck and apply cement (from a tube, of course) to the bottom, using the hole for access. One of the last steps in the assembly process was to glue a big plastic plate over the hole.
By modern standards those Renwall warship kits were pretty basic, but they did represent a step forward. The Renwall U.S.S. North Carolina/Washington kits, for instance, looked a great deal more like real battleships than the Revell and Aurora Iowa-class kits. And Renwall (as Airfix was doing at the same time in Europe) pioneered the idea of making a whole range of ships on the same scale - in this case 1/500. I haven't seen a Renwall ship kit (except at hideous prices at IPMS conventions) in at least thirty years. It would be nice if they'd resurface - along with some of the Renwall armor kits, which also had a lot to recommend them.
The Haskell-class attack transports were based on the C-2 Victory ship hull design. Their deck and superstructure arrangements were rather distinctive; in the long-range photos of big ship formations taken during the Pacific war it's usually pretty easy to pick out the silhouettes of the APAs. That's largely because they had extensive facilities for accommodating large numbers of troops. In addition to the troop berthing spaces, they had enormous mess decks and well-equipped hospitals.
The first APAs were converted liners and freighters; they went back to their peacetime careers after the war. The Haskell-class ships, however, were built for the purpose. I don't know whether any of them went into the merchant service after the war or not. I have the impression that most of them went into the Reserve Fleet. (My father's did - in Suisan Bay, California - and I remember when quite a few APAs were lined up at anchor in the "James River Reserve Fleet" near where I lived in Virginia.) I think a few of them may still be there, though most have been scrapped.
Some time back I ran across a website operated by a group that's attempting to preserve one of them as a museum ship, but I can't remember the web address. Navsource (www.navsource.org) has easily-accessible histories of all the APAs, with lots of photos.
I imagine it would be possible to turn a Renwall or Revell attack transport hull into a convincing merchantman, but it would take a good deal of work. It might, in fact, be easier to scratchbuild. Another good subject for a merchant ship model, though, would be the recent Trumpeter Liberty Ship. Liberties, of course, were found in civilian colors all over the world for years after the war.