I'm going to MEX but I don't eat pork products. A friend told me they still use lots of lard in their cooking - tortillas, refried beans etc are all traditionally made with lard. Is this true or can you avoid the tortillas and beans with lard and the rice with chicken stock?
You mention that you don't eat pork, but it seems that you don't eat chicken either. Your trip is do-able, but won't be easy.
Corn tortillas contain no lard. They're prepared using ground corn, water, and a comal (griddle). Foods such as huevos rancheros, tacos and enchiladas, all made with tortillas, may also contain lard, as the tortilla is lightly fried in the preparation of the dish.
Tamales are usually made with lard.
Flour tortillas are usually made with lard, although we are seeing some that are made with vegetable shortening. You'd have to know the cook--or read the label on the package--to judge.
Refried beans are usually made with lard, although some cooks are using vegetable oil.
Rice (sopa de arroz) is usually made with water blended with tomatoes, unless it's plain white rice. It's not usually made with chicken stock. However, some cooks (both restaurant and home) use tomato bouillon to prepare rice, in which case the base component of the bouillon is chicken stock.
Many, many Mexican restaurants use chicken and other meat-based stocks in dishes that you would never think to ask about. It's very difficult to be a vegetarian or vegan and eat in Mexican restaurants in Mexico.
Best of luck on your trip!