This is going to be a little confusing but I'll give it a shot to explain...
1: make sure the mde accounts are all linked correctly. If they are appearing with "name has a Disney account" under my family and friends then they are linked. anything else the accounts aren't linked yet. It will be on the left directly next to their photo and under their name that this will appear.
2: in order to see anything you schedule for them, they have the ability to block you from seeing this. You can only setup what you allow them to see from your account, they have to setup the opposite. It's the view all activities options when you edit the person your linked with.
As far as scheduling...
Everything will work the same as people in your party under your mde account. If your mde is linked to your DH, then you can do it for everyone but they also need to be linked to your account.
However all the rules apply to their tickets and reservations for fast pass. 60 days fp+ requires an on property resort. if they are arriving 2 days later than you, then they aren't at the 60 day mark yet.. etc etc... The system is actually pretty smart with popping up everyone you can select when you make the reservation if the accounts are linked correct and they are eligible for the fp+ on the same days you are.
I do this all the time with my daughter, we both have our AP in our own accounts, I generally have the resort reservaton and we're both linked together and either of us can make ADR or FP+ for the other. The system knows who has what tickets and what reservation, etc. I also have an upcoming trip with my sister where she has her own tickets and resort, and my daughter and myself have our normal setup. anyone can adjust anyone else as far as ADR or fp+ is concerned.