Question about friends linked on MDE

[ToyStory3]

We have an MDE account and use it for our trips. Next year we are going with another family. We will have separate reservations but are staying at the same resort, same ADRs, same FPP, etc. We are only going for 3 days. They've never gone to WDW before and really want us to just plan everything out for them. They don't even want us to confirm/discuss ADRs with them. They're overwhelmed by the whole process and not interested in trying to figure it all out. We are fine with that and it's how they prefer it.

So, do they need to set up an MDE account? They'd prefer not to if they don't need to. I would be able to manage their magic bands, ADRs, FPP, etc. right? Is there anything I CAN'T do for them through my MDE?

One thing I'm not sure of is whether or not they would need to set up an account just to give me access to them. Confused....

Thanks!