Bow-tie pasta can be used in place of the mini-lasagna noodles.
Beef sirloin steak is a tender and less-expensive cut of meat, which makes it a good choice for entertaining a group. You could also use strip steak, which is more tender but also more expensive.
Chipotle chilies are often sold canned in adobo sauce, which is a smoky, spicy chili-based concoction. Look for the chilies in larger supermarkets or Mexican markets.