SMD for “Surface Mount”.
Yes, for copper pads, otherwise you can’t create a symbol pin → footprint pad connection. See several articles in (Start Here) Frequently Asked Questions.
Yes, see What is the meaning of the layers in pcb_new and in the footprint editor? (KiCad 5 and earlier). (Should be still valid for v6.)
Nope. You need at least a mask opening (if you order the board from a manufacturer). See the article about layers linked to above, and How does solder mask layer work?.
Apart from reading all the FAQ articles etc. you can of course open an existing footprint in the footprint editor and see how they have been made.