Neither Passwords nor Contacts are shared with other members of Family Sharing. You don't need to do anything there.
Family Sharing - Apple Support
Family Sharing makes it easy for up to six family members to share iTunes, iBooks, and App Store purchases, an Apple Music Family Membership, and an iCloud storage plan. Your family can also share a photo album, calendar, and reminders, and even help locate each others’ missing devices.
After your family members join, the features of Family Sharing are set up on everyone’s devices. Here's what you can do:
- Download eligible music, movies, TV shows, books, and apps from the iTunes, iBooks, and App Store.
- Get an Apple Music family membership, then invite family members to join.
- Share family photos and videos. Open the Photos app, tap Family in the Shared tab, and add what you want to share.
- Use the Family calendar. Open the Calendar app to add, view, or change events and reminders in the Family Calendar.
- Share an iCloud storage plan to give everyone enough space for their photos, videos, documents, and more.
- Find your family with the Find My Friends app. Choose when to share your location with your family members.
- Help find family members' devices with the Find My iPhone app.
- Manage your child's account or turn on Ask to Buy. Children under 13** must join a Family Sharing group to use Game Center.