Burst photos are just need to be edited down to the frame(s) you want. Easiest to do on the Mac, you just select the burst photo and open it in Edit mode. There you’ll get a “Select” button to choose the keepers. When you finish you’ll be prompted to save all the frames or just the selected ones. Then the burst will be converted to individual still images.
Live Photos can be turned off by selecting them and choosing Image > Turn off Live Photo from the Photos menu. You’ll have to test whether that enables uploading to Amazon. And for the future, if your family is taking unwanted Live Photos, they probably have left the Camera setting on default, which always reverts to Live Photo when you launch the Camera app. To make it a manual setting, they have to go to the Camera settings and turn ON the Preserve Settings option for Live Photos. That makes the setting stick to the last used setting so if they turn it off [by touching the Live Photo symbol] then it will stay off.
The Shared Album file quality gets a bad rap, I think, because it’s not nearly as bad as we first thought. Allowing unlimited full size images in Shared Albums would choke the system and make large Shared Albums unacceptably slow to load for viewers. So the default image resize is to 2048 pixels on the long side. 5400 pixels for a panorama. For a standard format image, that gives you a 5×7 inch picture at typical photo book resolution and you can upsize it to a full page bleed on an 8.5 x 11 book without getting a low resolution error. For a photo print you can go even larger. So for typical sharing use – making 4×6 prints or adding to a page of pictures in a book – the Shared Album sizing is not much of a problem. In the case of a larger wall print or to crop into a shot, then, sure, that might warrant a better file, but as a tradeoff of convenience for quality, the Shared Albums settings aren’t a real problem. And easy alternative, though, if you really want to pass around full size images or videos is to create a Shared Folder on iCloud Drive.