My recipe calls for shortening, I want to substitute lard for the shortening, will this work? Or can I just use butter?
Yes, and also yes. Moreso lard than butter, as butter has significant water content, but it often does not matter enough to worry about. Most recipes that have been around for a while probably started with lard.
For MOST things, you can simply pick any of the three and it will be fine, or you can mix them if you like.