Number of employees is relatively simple to figure out. Let's say the store is open 9 to 9, seven days a week (simple for calculating). That means you've got 84 hours to cover, usually with a minimum of two people. Although you could slide down to one person from 9 to 10 in the morning and from 8 to 9 in the evening, assuming you have no real sales during those periods. (The reason you need two people is to cover lunches, breaks, bathroom runs, sickness, et cetera.)
You'd probably want three people in the store from 11 - 6, although this depends upon sales volume. Obviously during Christmas, you increase your sales force. So going with three from 11 - 6, this means you've got 217 employee hours to cover.
One of these people will be the owner/operator. If two people bought the franchise, you'd probably see both of them working here. The owner would be the third person during the critical time periods, and would be putting in somewhere north of 50 hours a week. Probably very far north of 50 hours.
Owner would deal with what purchasing needs to be done, but for franchise operations, this isn't much. If national decides you're going to promote green llamas for Valentines Day, then so be it. Owner would do the purchasing, bookkeeping, and everything else to do with running the business and going out to help run the register or stock shelves as needed.
If a single owner, you'd have one or two other full-time, maybe three. These are your trusted employees, dealing with opening and closing when the owner can't be there.
So going back to the 217 hours, we'll subtract 80 hours for two full-time employees (you don't want to pay overtime). This leaves you with 137 hours. Owner covers 60 hours per week (more hours the owner covers the more money the owner doesn't have to pay out). That leaves 77 hours. Four part-time employees at 20 hours per week or eight part-time employees at 10 hours per week covers the rest of it.
Best of luck,
Jim Clark-Dawe