If you want to own the lot, you should change the lot to be something like a Hangout or anything else than visitors allowed. Then you would be able to buy it like any other purchasable lot. Unfortunately, you don't get funds like you would with a resort. You can't actually be the cook in the restaurant yourself, which kind of disappointed me.
Once you hire new chefs (you can change the quality of the chef and choose which foods to serve, etc.) the bistro should start running on its own as long as it's between the hours of service (which you can set with the oven too).
