Well, the "fishy tails" hypothesis only works if you also assume that the Foliate Head itself is covered in scales rather than leaves. The bad photo you linked to doesn't show it well, but it's clear that whatever is covering the midriffs of the emerging club-wielders is the same as what covers the head of the "foliate head" (i.e. leaves). It's much more visible in the clearer picture Here. Particularly in the more-visible figure on the right, you can see that the vein structure in the leaves at his midriff is identical to the vein structure in the leaves on top of the the foliate head: each leaf has a strong central vein, and consequently looks not much like a fish scale.

In addition, you can see that their shields are flowers, and each has a big leaf growing out of his head and one growing out of his midriff.

I grant that their bottom parts below the leaf-skirts do not look like legs. What it looks like more than anything is that there is some kind of seed-pod, trumpet or tube growing our of each ear of the foliate head, and standing in each tube is a Green Man. (Note the marked absence of scales on the tubes, as well) But those are definitely leaves, as the foliate head's head-foliage demonstrates.

The fact that a different bench-end features dolphins is irrelevant. It's like me telling you that Santa Claus is associated with elves in popular culture, and you making the retort that he's really associated with reindeer. I'm not drawing any conclusion from the fact that the foliate head is connected to the wild man/green man except that the connection exists, and existed in 1534, which is 405 years before 1939. All manner of other connections also existed, without negating this one.