I believe epoxy over vinyl/poly -ester type resin is fine but the reverse order is not. I've often wondered about people who've varnished their boats and if it has to be removed before adding a coat of epoxy.

I did a boat in worse condition about five years ago. All I did was clean it, then a very light sanding in the few shiny places it had left (it had a lot more use as in most was pre-roughened by 'normal' wear so that boat was quite a bit fuzzier than yours). Then I rubbed it down with denatured alcohol.

With the canoe prepared I went to the hardware store and got two double syringes of quality epoxy, came home and spread the full contents of one on the canoe with a credit card just moving it around like a snowplow much as you would when spreading contact cement on formica and particle board. A roller sucks up more epoxy than the canoe will IMO.

A few hours later while it was still slightly tacky, I mixed up the other syringe set and spread it out the same way. It takes 5 minutes. You do want to work fast but don't use the quick epoxy as it's more brittle (harder) when cured. I only did the bottom and it was still rough. If it were my canoe I'd have done another, more 'dust free' layer or two but it was good enough for my piece of mind and it can always be re-coated and buffed.

It filled the deeper gouges nicely and took care of all the fuzzies which are why I bothered spending $10 and time to begin with. I know there was at least one sag/run and there may have been a couple more if you looked closely but the owner didn't mind and I'm told it's still holding up fine - not pealing off at least. Epoxy is really forgiving stuff.

That #7 - if it feels structurally funky you should probably add some glass to that area first.

That's my suggestion. Good luck, have fun.