skiP.E.I.If I see smaller independent brands I think "these guys know what's up"
i.e. ON3P, Moment, Icelantic, Skevik, Flylow, Strafe, Trew.
Also needs to be a good range of boots so there is something for all different foot shapes.
If I was getting poles, I'd always choose telescoping.
I feel like having jigs even for bindings you don't sell would be useful since people will inevitably come in with them to get mounted.
When I was younger, and even still, free/cheap stickers would get me psyched.
I have trouble finding 1. compact things of sunscreen for spring touring 2. hardware like T-bolts for boots. It would be sick for those things to be available in a shop. Also standard tools/multi tools
I would usually buy lightly used or demo skis. Also I always thought it would be cool if you could trade in a lightly used pair of skis with the value going toward a new pair.
The best thing about a shop is it can be a community hub where you can hang out and have a chat without pressure to purchase anything. If there are movie premieres, art shows, mini ramp, anything like that it makes it a really welcoming place!
The only thing I'll add to this is careful with too many smaller more boutique brands. I manage a freeskiing shop and if we only carried those brands you listed (we do carry a couple of them) we'd be out of business real quick. As cool as those brands are and as much as I like their products, you won't make it very far without having at least some of the more basic brands. However, it's pretty easy to appease the masses while still having "cooler" skis as well, i.e. brands like Armada, Atomic, Volkl, etc.
For OP, find the balance of having those small brands that will attract customers like you'd find here on NS, to brands/products that will attract the masses. Although you can't always get every segment of the market, here in Breck we will still always get beginner people walking in asking about brands like Helly Hansen, Spyder (although spyder is at least trying to get back into freeskiing at least), etc. Which then it just depends on how good of sales people you have to go beyond just saying "sorry we do not" to "sorry we do not, BUT we do have some very comparable products".
For the OP, get a good sales staff that goes above and beyond and you will be rewarded. There's so many online tools for training your sales staff that you can take advantage of. The best piece is always the first impression customers have in relation to the level of customer service.