It is indeed complicated. I think (with help from Dr. Graham's book) I can sort out most of the Revell kits; when it comes to the Heller ones I give up.
The Revell "Yankee Clipper" was just the Flying Cloud in a different box. (I think even the figurehead was unchanged.) According to Dr. Graham, it was released in 1973. (One little curiosity about that kit: in its first appearance as the Flying Cloud, in 1957, it had a full set of vac-formed "sails" - except that, for some reason, the fore topsail was omitted. A model built from that kit, with that huge gap in the sail plan, would look pretty silly. I believe the fore topsail was included in the "Yankee Clipper" reissue.)
The Flying Cloud also, of course, was the basis for the several appearances of kits labeled "Stag Hound." That was a Revell scam - not quite of the magnitude of the "Beagle" stunt, but close. The Flying Cloud and Stag Hound bore scarcely any resemblance to each other in reality.
The Golden Hind kit (one of my favorites) got issued by Revell under two other names of which I'm aware: "Spanish Galleon" in 1974 and "Pirate Ghost Ship" in 1978. I never bought either of them, but here's what Dr. Graham has to say about them:
H-367 Spanish Galleon with sails. 1974-76....Modified H-325 [sic; should be H-324] Golden Hind with new figurehead, row of shields added to sides, two lanterns on stern, and new stern carving. Cross, saint decals for sails.
H-519 Pirate Ghost Ship. 1978....Skull-and-crossbones decals for sails. Glow in the dark paint. This is the H-324 Golden Hind (1965).
Both those reissues obviously were marketing stunts. The Golden Hind was no more a Spanish galleon than H.M.S. Cossack was a Japanese battleship.
The "Elizabethan Man-o-War" was a reissue of the smaller of the two Mayflower kits. Dr. Graham says the following about it:
H-389. Elizabethan Man-O-War with sails. 1975-77...."E.R." decals for sails. String for rigging. This is the Mayflower without its lifeboat and with twelve cannon added. Reissue of H-327 (1966).
I believe the original carved flower on the transom also was removed. That one isn't quite as unreasonable as the others. "Man-o-war" is such a vague term that it's meaningless; the ship in question pretty obviously is a merchantman, but plenty of ships of that description got pressed into service during the Armada campaign. It's conceivable that a ship of the period just might have looked something like that.
Beware: the Revell Flying Cloud, Golden Hind, and Mayflower all have appeared at one time or another in Heller boxes. Our good friend Michel vrtg has alerted us that Heller reissued the Golden Hind under a particularly bizarre name as a "corsair," or something of that nature. I sometimes wonder how the conscientious artisans who designed the original Revell kits felt when they saw their creations bowdlerized by all those reissues, which, in many cases, amounted to downright deceptive advertising.