Russell, first off, I love tiny homes. Having designed, built (everything DIY), lived in for two years and still own a tiny home, I really like this idea and have thought about it a few times. What is being described is essentially rebranding a resort. Instead of using the words cabins and lodge, you're saying rustic tiny homes and venue. Mount du Lac Resort has a bunch of these mini cabin/tiny houses right at their ski hill in Superior, WI.
It's good you got the county involved so you can bounce ideas and desires off of them early. Note that as you get closer to the twin ports/cities/towns you start to have to deal with their jurisdictions, as well as those set forth by townships but I'm sure your aware of this as it is listed on the STR page on the county website. I wrote about it in another post a while back about STRs in/around Duluth.
As far as costs, Tiny Homes are a bit odd. You have to meet building code requirements in a tiny envelope so economies of scale don't quite work out for single units. If you build 30 of them on the same property, you could centralize many of the services which would help reduce costs but if you can't, each home would require all of it's own utilities. Well, sewer, electric (meter, panel, etc.). The tiny house community has done a good job of rebranding trailer houses as tiny homes on wheels but after staying in a few trailers, I would stick with permanent foundations in order to create a better product and get a firm hold something that goes up in value.
I like the smash burger bar idea. If I could add two cents to that jar I would look to pull something local in, especially if you're near Duluth. Duluth is a very 'local-big city' as in, the people love and support craft districts and purely Duluth things. Duluth Grill, Love Creamery, Bent Paddle, Grandma's, Duluth Pack, etc. are typically far busier than Cherry Berry and Crooked Pint. Having a Duluth-esk experience would help draw people in. I'd recommend 'King of Cremes' in Duluth for smash burgers. Here's a copy of many of my local favorites: Local Duluth Map. If you're looking towards Ely, in the 9 years of living in Duluth, I went to Ely once but I went up the north shore countless times. That is where the majority of the people are going to be who would keep your occupancy rates up throughout the entire year.
Anyhow, if you have any questions or need to pick a brain, shoot me a DM. If I don't hear from you, good luck with your project! Lots of work ahead!