what is the different between the Multi and the ones that aren't multi? I don't understand because the mutli templates are the ones that are showing.
If a customer only buys more than one product the multi template is used. Otherwise the standard one is. Correct me if I am wrong but I think that is how Alex set that up. So just make sure if you update one of those you update both of them so they match.
Not exactly. If you enable options aMember CP -> Setup -> Advanced : "Select Multiple Products ..." then "multi" templates will be used.