Hi Randy....as far as buyers not wanting to apply to be a buyer on EW when being sent a guest pass, there could be several reasons. But, who knows, maybe after a successful, positive buying experience via a guest pass, they decide to enroll. It is free to be a buyer on EW, however, EW vets buyers and not all buyers make it through that vetting. So, it is possible to apply, and not be accepted. Just like if you were to vet a buyer yourself and they did not meet the criteria you were looking for.
For IG...Google how to use IG and you will find a lot of helpful tips. My Mom is 76 and she googles everything to learn how to do something. She was on IG before I was.
For shop updates, I actually do not use the shop updates with my social media. I just use that feature for my Etsy shop.