I have read through this and hope you will spend a lot more time planning this. I hate to say it, but nothing I have read shows me you are ready. I have owned my own retail store for years. You better listen to these folks telling you you are undercapitalized. You keep saying how you have spent years "thinking" about how it is going to work out. Stop thinking, buy a calculator and start figuring out how you are going to get paid.
Do not think you are going to just have fun and money is not important, etc. You will have a job, you will have to work like a dog, you have people hate you, cuss you, steal from you, and take you for granted. They will complain that you don't have this and that and go buy it online, shipped free with no sales tax for less than you can buy it for wholesale.
Do you even know how much it will cost to heat and cool and light and house and show and dust off and market and insure and pay taxes on a single pack of yeast in your store?
You sound as if you are planning on being there for opening day, with little thought to how you will stay afloat for the two+ years it will take you to start making minimum wage on a weekly basis. Do you even know how much inventory you will have to sell to make minimum wage? Do you know how much MORE inventory you will have to have on hand because you will not sell everything in your store every four months, that is not how it works.
The "Aw shucks, I just love beer" attitude is going to end up with you out $30k+ and a year of your life that you would rather forget. Retail sales has nothing to do with how long you have been homebrewing or that your wife went to business school. You close your eyes and imagine how cool it will be to hang around and talk homebrewing, that cool daydream is just under 10% of what your job will really be like. The rest is hard and thankless.
Yes, you will have some nice moments. Yes, you will have loyal wonderful customers. You will not have enough of either of these to keep you fed and make it worth your while. The rest is going to be work and figuring out how to get paid on Friday.
Do not think you will survive without pay, because you are living off a retirement check. Going to work is work. How long are you going to take the day to day of retail ownership as you pump in money for little to no pay. I will tell you. NOT VERY LONG.
You want to make money in retail homebrew supply? Then apply for a job at the other homebrew store in your area and work there for six months. Profit on day one, no money at risk, guaranteed return. If you are still there and haven't returned to retirement after six months to a year (it is required that you work through Christmas season to understand how seasonal sales work), then you will have a more realistic notion of what daily life in retail is like.
I think I could turn this into a book, but I am just going to stop here. I hated to do it, but you needed a "wake up" slap across the face.