iCloud Family Sharing

I am the admin for our Family iCloud account. With the account I have 2 iPhones and 1 iPad on the plan (no kids) my question is should I be able to see all the content on all 3 devices? We only back up pictures, Contacts and Calendar. My iPhone is the 8+ other phone is a 8 and the Ipad 7th generation.

I am not to savvy at using ixxx products even though I have had iPhones for several years.

Thanks LeenShe