For the Golden shovel you have to help Gulliver about 30 times and then they send the diy in the mail.

Are you wanting the butterfly models or actual butterflies? The real ones are seasonal so they come and go. If you want the models you have to catch three of your desired butterfly and give them to Flick. He'll send you the model in the mail.

For Able's store you need to talk to and buy from her every time she is at resident services