Will I lose my families data if I consolidate to my iCloud+ storage when doing iCloud One?

Whether you use a family iCloud storage plan or individual plans, everyone's iCloud storage is stored under their own personal Apple ID. The only difference is the billing and the amount of space available. Data is not merged.

Also see the following from Share iCloud+ with your family - Apple Support

When you share an iCloud+ subscription, everyone in the family group uses their own account. That way your photos, documents, and other information stay private, even though you're sharing access to the service. You simply share the features and space available in iCloud+ with your family members, so you only have one plan to manage.

Note that data can be merged in an iCloud Shared Photo Library but that is a completely different thing than sharing an iCloud storage plan (i.e., you can have an iCloud Shared Photo Library whether or not you are sharing an iCloud storage plan.

The following may also help. With Family Sharing, everyone uses their own Apple ID. See: Family Sharing - Apple

and

What is Family Sharing? - Apple Support

Note that if everyone in your family is currently using the same Apple ID for everything, moving to individual IDs is not usually easy.

Use of a common email is no longer advisable for iCloud. If you use a common email for iCloud, things like recent calls, iCloud Contacts, iCloud Photos, Notes, Reminders, Photos, Passwords, Safari Bookmarks, etc will sync across the family and that can cause problems. For example someone else in the family can delete some or all of your iCloud Photos from their device and that will cause them to delete everywhere, including your devices.