There have been several extensive threads about buying an existing business, and they’ve presented many different aspects of doing so.
I only have two comments on your post: first, 5.5 years is nothing. Be sure you have something in writing from the landlord regarding renewal leases or options. If, as you indicate, the area is rapidly being upgraded, you might find yourselves in a nightmare in five years if you don’t prepare now. Second, I had a place – a bar – with a lotto. I didn’t find that the work involved was worth the small amount of money you earn. What happens if the lotto or the mega hits a big number, and you get a lot of people buying tix right in the middle of your lunch or breakfast rush? Will the added income make up for the loss of good will among your regular customer? Plus, whatever money it is doesn’t come without effort. Just my opinion, but to me the lotto is best in a convenience store or a candy store.
Actually, I have one more comment. Think long and hard about adding subs. I would believe that you’d be much better off making sandwiches on bagels.
Either way, good luck.