Ok... two points.
First - have you ever fished out of a small boat? A higher freeboard (distance from waterline to gunwale) is often a good thing when it comes to safety for a sailboat. It can be a bit problematic for boating larger fish. Not that it can't be done... I just don't regard it as optimum.
Second - given the discussion so far, I can speak a bit to the applicability of the GIS. My background is that I'm an approved builder for Storer, and built our first one over 10 years ago. As a family boat. Because the kids (10 & 15) wanted to learn to sail, and despite a life full of boaty activities, I had never sailed a small boat. I welcomed the opportunity. As it happened, though, we used the boat for two years, quite happily, with oars and outboard only... before we put the sailing rig on her. Fishing, boat-camping, and general messing about --
It's a smallish boat for the duty you have in mind. If you unstep the mast, and bundle the spars/sails along one side of the boat... you could fish two, but no more for casting. Three if you troll or handline only.
At a typical finished weight of 130 - 150#... it's a very light boat. That's both good an bad. Bad - no inertial to punch thru a headwind with chop while rowing. Not much 'carry'. Good - much easier to launch, retrieve, and jockey around the beach if you go ashore to eat lunch, explore, play, or dig a few more worms.
Of all the boats mentioned - The Goat is the most boat for the money/time invested. By far. A great value. As a benchmark - we spent about $2,600 on ours. That includes everything except our labor. Plywood, lumber, hardware, paint, hardware, lines, sail, fenders, flares, bailer, a small used outboard, and a very used trailer. Again... of all the boats mentioned... that's about the least you'll need to spend.
The Goat - with its dory-shaped hull IS tiddly. Not a lot of initial stability. If you are alone in the boat, and stand on the gunwale, you WILL go swimming. The flip-side is -- the more weight you add, the more she gains in stability. A second body changes the equation substantially. Same effect can be achieved when solo, by carrying a pair of tire-store traction-sand bags inboard. In order to learn to sail, I used two 70# bags as 'training wheels' - and it made all the difference.
As a sailboat - she is great. Excellent, really. Example - our GIS matched a Core Sound 20 for speed, and was quicker around the buoys during one race. And the balanced lug rig is simple for a beginner, and easy to manage for someone with their mind on fish. My own nascent sailing skills will never outgrow her. And yet, she's perfectly capable of 'don't make me set my beer down' sailing. It's up to you.
The bottom line is - you are attempting to find a boat that will manage two quite dissimilar duties. Because of the general capabilities, the GIS would not be a terrible choice. And... if value, relatively low cost, and light weight are priorities... it rises up toward the top of the list.
The biggest question mark, for me, is your waters. Is she big enough to handle your home waters. Without knowing more, I can't tell. But I have (even the first summer - as a rank beginner) sailed ours in 25 mph winds and 4' waves. I've even launched her thru the surf, rowed around beyond the breakers, and come back in. That's rolling the dice, though. Broaching in the waves might net you a scattered collection of toothpicks instead of a boat.
Hope that's helpful.