IOS – What happens to 32-bit apps on a device after an iOS 11 update

From a technical perspective your subscription is only valid as long as you're paying for it. After that Apple's servers return the same response for you, as they would if you had never subscribed.

You will probably still keep access to all your issues, although restoring old issues has to be implemented by the app itself. For example wired magazine requires you to create a wired account to later restore all magazines. (But even without the account you can keep your downloaded issues as long as you want. I expect that to be standard across other magazines as well - but again, that's up to the publisher.)

Before Family Sharing, you could take someone else's iOS device and sign in to the app store with your account and download all/any apps you choose.

At that point, your password was needed to update, but signing out didn't delete the apps or in any other way prevent them from working. Let's set aside in-app purchases for the time being.

Family sharing changes this in that when someone joins the "family" - their Apple ID is used to download and update other family member apps. They do not show up in your purchases, they show up as the other named family member's purchase. All that changes is the password needed to install and update.

When you as a family member remove yourself from the plan - you get a warning that lists what will happen and basically, you immediately lose access to the purchases, photos, calendars and other items that were shared in the plan.

Rejoining the family would then let you re-download and re-sync the items.

You'll probably want to find a better way to use the family service than routinely joining and leaving or skip the family share and use the older method of signing in to multiple devices which doesn't immediately remove/revoke the items.