Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Not that I know of which works with the current Play Store.
You can turn off automatic updates, but the update reminders will still sit there cluttering up the "my apps" list. I have a few that I'm not updating.
Being rooted, I keep backups so that if I ever make the mistake of updating an app I didn't want to I can revert it.