My daughter and I are gluten free and totally enjoyed the experience. Just notify them in advance...they are very accommodating. The only part we had to skip was the churro tasting at the end, but we were too stuffed full of delicious tacos at that point to eat them anyway.

correction Tour opertaor

The walk around El Centro is typically flat, but some of the sidewalks can be a bit difficult for people with mobility issues (due to height of the curb and some uneven sidewalks). If you feel that you can navigate around El Centro unassisted, then you should be okay.

Quite close ; probably 10 minutes at most

No this is not the tour for you.

No entrance fees on my tours. Tips are always expected for guide etc.

Was it Zapata Bar? The big black and white wall painting of Emiliano Zapata was what I noticed when I first walked in. I believe I tasted a mezcal (not a tequila) there with the chili powder and I recall it being a slice of something citrus but I don't recall if it was an orange

It depends on the places that is being visited (each day of the week is different as each of the stands/restaurants have different days off), but there were only three places that I was at on my tour that even had the drinks available to buy beer. Of all of the places, Zapata Mexican Bar would be the only place that had liquor, but we were there to taste Mescal (did you know that Tequila is a type of Mescal? I learned this on my tour). However, please note that the visits to each place are pretty short and you would need to drink your beer(s) pretty quickly if you want to keep going to the other spots.