Cheat sheet for the AppID? The most concise I have is my blog Tips and Observations for getting Web AppBuilder - Developer Edition Installed
For possible sharing, the links above of searching and looking thru a few more on geonet might give you more options....or more deadends. I think the true sharing thing is the AGOL/Portal named user licensing issue, that is, each user that logs in will have a appID....I haven't tried to see if that could be shared by other named users (and not sure if that is legal)
Since the WAB files are just system files, sharing or copying the files on a network I think could be done, but I'm sure there would be locks and not sure how you (the system) would handle multiple editors.
Also, if you haven't bookmarked it yet Web AppBuilder Developer Edition - Customization Resource List