Every dream of a new start up business needs the same basic market analysis and planning as any other business. Too many people lose because they start a business that appeals to them but forget that it's the customers who will make it either a success or a failure.
You must first consider whether you can supply what they want, in the right way, in the right place at the right price. You need to estimate costs - rent, services, wages (including your own), stock, stock shrinkage (yes, customers and employees steal) and so on. Mark up the costs for profit or return on capital and you have an idea of what your sales volumes need to be.
Then you have to find out how much your stock items would cost and for how much you could sell each of them. Compare that with the minimum necessary sale volumes.
You have to be tough with yourself when doing this.
I think that specialist items are best sold on line. It's the place for speciality products. It's not as glamorous as having a nice little shop but profit is more important and a profitable business will last.
Good luck with your ideas. Enterprising minds are an inspiration to others.