VTS are not all that bad, if you breed them right. I found people go for wider fins, even VT, as long as the fins are full, clean lined, and even ;)
1. Heat and electricity will depend on each idea of a place. Leasing will be a pain in the butt, whereas having it "in home" (aka using a garage or something) or buying a small place (even a trailer home? Those are dirt cheap). If using 100 heaters individually, costs do build up. But if I work it out right, it should be cheaper (hence why I use a small room heater). However I will note 10+ gallons may need a heater even with a room heater (IME). As for rent, depending on the area, town, etc, it can cost a lot or very little. If finding people interested, or perhaps being able to obtain a business partner it would not be as expensive.
2. Advertising includes locally. Currently I will be supplying the family-run pet shop, and place brochures with the fish. I may or may not supply the new pet shop in town, because by the sounds of it they want quantity over quality and I do not feel up for that practice. I also have a blog, and have found more and more people on this site that are close by.
I may be able to also participate in the Farmer's Market, where hundreds of people pass by. Both from this town, and from out of town. People I find, like to learn through positive experiences and seeing for themselves (seeing is believing). I also post on FB, in the buy and sell of my area, and I have been contacted repeatedly by excited people or people with questions to which I satisfy with answers.
3. I think live plants would be another thing. I would have separate tanks just for plants, and considering my plants seem to grow a little too well...

I am sure I could do it.
4. Benefit for showing off the bettas: Now, I am not going to make people pay 40.00 for a fish. It's ridiculous. First off I do not ship them in, therefore do not need to make back 5.00-20.00 per fish. Betta Fish are only the beginning, so right now that is the focus. I did make sure to ask around, place polls, etc to see what tail types and colors are most desirable and built my breeding plan around that with a few of my own desires (trying out the double crowntail). Even if the people do not care where their fish came from or how their fish were bred, they can still get the satisfaction that they are healthy. Those who care, I will be able to show pictures of the parents and tell them where the parents came from (store, person, province etc). Currently my price is 3.00 for this large spawn, while the next may be 5.00. When I get my quality half-moons this spring, they may go for 10.00. But my prices will never be as outrageous as any store for the "rare" tail types.
5. Considering in my particular area there is no petsmart or petco or petcetera... I have a higher chance than I would in the city. The only other store I may end up supplying anyways, which then I can avoid those poor blue bettas from being sold and a person having their fish die months later from the disease (all but one blue betta I have gotten has had that disease and perished from it). If they want to buy a 3.00 betta (sale in petsmart) then they must pay 20.00 to 40.00 for gas depending on vehicle and weather of course.
6. I would eventually sell the supplies as well. And the idea of getting kids to get better educated about fish is a great idea. I find that if a parent is naive, but the child knows something is wrong the kid will speak up and say so. I've seen it numerous times. I have seen one kid tell their parent that their bunny needed a bigger home!!
7.A license is needed, but is not impossible. It's basically writing up what you are doing, getting it certified, etc. I think there is a course or something you need to take in order to be able to sell pets (no idea if it applies to fish? Never know anymore). The closest person(s) to ask is basically the government itself, aka business bureau or whatever.
To take a course in college, would bankrupt me. I'm someone who has been in poverty, who is too
stupid to their standards to make it to college. We do not have community colleges. I need to be a stupid mathematician just to do anything involving college, unfortunately. I DO know people who have taken the course however.
Everybody pays taxes. You pay taxes on the money you make HOWEVER if you claim expenses as BUSINESS EXPENSES you make back the money put into the said business. Especially if you can get a big guy on your side, and present the store idea well. I could also ask the owner of PetsGO how he got into the store, and what he has had to do.
I will probably have a few types of fish there depending what people want, and what sells the best in other stores (finding out why they sell the best, etc). The sump idea is a great idea since then it does keep the water circulating. However for any new fish they will be quarantined in separate running tanks...