Questions to understanding/installation/planning ?

Hello everybody,

in our testsetup we have 2 Windows 2012 R2 Domain Controller, 2 MS RDS Hosts, 1 MS Licence Server (also IIS)
an one machine as prefered 2X RAS Server.

The 2X RAS Server is a AD member Server.

For better understanding/installation/planning i have a few questions:

1. To login in 2X Application Server Console, i have to use the local administrator account NOT "ADname\Administrator" ?!
Why ?

Which kind of server is for 2X RAS Server possible/recommended ? AD member or StandAlone/Workgroup ?
I think AD member is correct.

2. Which is the recommended setup for the 2X services ?
All 2X services run on the 2X RAS Server.

3. Is the MS RDS Broker also service necessary ?

4. Are there any basic architecture sketch available ?

Best regards & thank you very much
Andreas