: The plans for my S&G canoe call for taping the inside seams but not glassing,
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If the plans call for a fillet at the inside panel seams, to be covered with glass tape, then that's what I would do as a minimum. The tape on top of the structural fillet is an important element of the structure. Besides, the tape is probably heavier and stronger (say 9 oz fabric) vs the 5 oz or so fabric you are using to protect the panels.

The point of fiberglass on the floor is to protect the epoxy layer/wood on the floor from sand, etc. that might be ground through the coating of epoxy on the inside of the boat. If no sand or abrasive will ever be carried from sneakers or any other source in to the boat, you probably don't need the protective fiberglass cloth covering. But I would cover the floor with fiberglass cloth at a minium. Even if your friends use a piece of indoor/outdoor carpet to protect the floor, sand still seems to find its way under the carpet and causes abrasion.