Some of the older villagers who have watched Naruto grow up would be regulars. They would come to support his business and also to reminisce about the old days. And don't forget the jonin who are always on the lookout for a good meal. They would appreciate Naruto's hard work and the unique atmosphere of his restaurant.
Ninjas, of course! They would come to relax after a long day of training or missions. Also, fans of the ninja world from within the story would be there. Maybe even some of the village leaders would stop by to show support for the local business.
The regular customers could be Naruto's friends from the ninja academy. They would come to the bar to relax and catch up on old times. Also, other ninjas from the Hidden Leaf Village might stop by after a long mission.
Well, first of all, the genin teams would be regulars. They need to stock up on basic ninja equipment. Then, the older ninjas who are retired might visit to relive their younger days by buying things they used to use. And don't forget the wandering ninjas. If Naruto's shop becomes famous enough, they would stop by to buy rare items or get some rest and information at the same time.
His old ninja friends like Sasuke, Sakura could be regulars.
His ninja friends like Sasuke, Sakura, and Kakashi would surely be regulars. Sasuke might come to buy things secretly to support Naruto's business. Sakura could be there to get supplies for her medical ninja work if it's a general store. And Kakashi would stop by for a chat and to pick up some new reading material if Naruto sold books.
Mostly wizards and witches, of course. They would be the main clientele as they are the ones who can fully appreciate the magical elements of the restaurant. Students from Hogwarts during Hogsmeade weekends or holidays would also flock there.
His old friends from Hogwarts would surely be regulars. Ron and Hermione would be there often. Neville might come to relax after a day of teaching Herbology at Hogwarts. Luna could drop by to share her latest theories about magical creatures while sipping on a strange - looking drink. Hagrid might also be a regular, though he'd need a special - sized chair.
Other potion shop owners might visit too. Not as customers in the traditional sense, but more to check out the competition. They might be curious about Harry's unique potions. And then there are the local wizards and witches in the area where the shop is located. They could need potions for daily life, like a potion to make their gardens grow better or a potion to keep their pets healthy.
Well, the regular customers could include some of Harry's old friends from Hogwarts, like Ron and Hermione. They would support Harry's business and enjoy the unique atmosphere. In addition to that, supernatural hunters from the Supernatural world might stop by. They could be looking for information about certain supernatural beings that might be lurking around the bar. And of course, there would be the local supernatural community, such as witches and warlocks who are not directly related to Hogwarts but are interested in the mix of magic and the new - found supernatural elements in the bar.
Hermione would probably be a regular. She'd come to the cafe to study while enjoying a warm cup of Butterbeer latte. She might even bring some books from the Hogwarts library to read there.