Being a bartender alone is a full-time job, let alone running your own business. I don't think anyone would bat an eye at that taking up most of your time.

[ ...not that Kim doesn't suspect that she got up to the exact sort of trouble that Cloud and Aerith do, but he's not going to damn her by association. She could just be a good friend. ]

I'm not sure what niches you'd be looking at. Something to set yourself apart. Like... a karaoke bar, maybe? Or one that serves some sort of food you can't find in the rest of the city? The best way for you to figure it out is to check out the competition. Which might be useful for getting you a job in the interim as well.