Have a wonderful time with your shop and welcome to the Quilting Board! We love offering our perspectives.
Here are my first thoughts after agreeing with what eveyone else has brought up.
If you are thinking about selling sewing machines, please make sure there is someone nearby that can do repairs on the brands you sell. I know I don't want to buy a machine and then send it off to get repaired. I want to maintain my relationship with the store I bought it from. Perhaps you can get certified to do the repairs?
I have been to shops where they would rent accuquilt dies by the hour to folks who didn't necessarily want to buy the system themselves. I am not convinced that there is a lot of money in that unless you wanted the dies anyway.
Longarm quilting seems to be a trend some shops are leaning towards as well. Would quilters in your area want that service? If not, are you willing to do longarm quilting for folks mailing things to you? (In which case your online website needs to be up and running really well.) Those machines cost a fortune so make sure you can make money off a longarm before you commit to it. Unless you just want one, of course.
Expect the best and make contingency plans if the best doesn't happen. I have talked to owners who love ther online presence and others who hate the complications of a an online presence and so don't sell online. If the local business generated isn't enough to keep things up and running, are you willing to consider an online presence?
And for the partners of those who quilt, make sure you have affordable quilting-themed knick knacks for them to buy when getting fabric is just not intriguing. Mouse pads, band aids, etc., silly things that won't fill up a lot of space and won't cost you a lot of money, but give nonfabric lovers something to look at and consider as a fun last minute gift.