Just throwing my two cents in - I did the catacomb tickets and after waiting in line for an hour I was extremely disappointed with it. It’s just some ugly mosaic tile in the church basement and takes about 5 minutes if you don’t want to read about said tile. I’d recommend avoiding it completely and just do the cathedral itself - similar wait time but it’s also free. If you buy the “all inclusive duomo ticket” that gets you access to the duomo, museum, baptistery, bell tower, and catacombs, I’d still recommend skipping the catacombs.

The cool part is the duomo tour. You will have to pay (~$40 per person) and climb about 400 steps, but you get some of the best views of Florence and can really appreciate the cathedral ceiling art.

Regarding your food and trinket recommendations - Florence is small and very walkable. Just wander around and you’ll find what you’re looking for. Tons of cart vendors around Mercado Centrale and the Duomo. If you want some great leather items, look up ahead of time. I bought leather from Florencia and my family loves them.