a place for bands to practice

More Balls than Most

You should be asking the Franchisor this question. They sold a business model that must be successful elsewhere otherwise no-one would buy it. They should be experts at helping you tweak it for success.

hiring anyone worth a shit

Sorry to be the bearer of bad news, but a new retail shop has an extremely high failure rate in the first 3 years.

Get good at marketing fast! social media, spend money, run promos, pass out stickers, hold a BBQ, take action.

FDD is just a disclosure document. They don’t necessarily need to give you contacts of other owners, though. Referrals from other franchisees would be key for your decision making process I would think.