2 Active Directory domain controllers on the same internal network.

This is a first for me and I need some help. I have been tasked with setting up a new separate primary AD on our existing network for students that already has a primary domain controller for our staff and students. My IT Admin wants to move the students to their own AD for security reasons. The layout will look like this first one will be for staff ex. abc.subdomain.domain.edu and the other for students ex. def.subdomain.domain.edu both the domain and subdomain are named the same. All DHCP will be handled by the firewall and if I am saying this correctly all DNS on the both ADs will be forwarded and the internal print server for students will have the A record added manually. So my questions are, is this a correct setup, are there any special considerations I should consider while I am planning, is this a good way or is their another/better way to look at doing this, or am I doing this incorrectly.

Thank you for any help and advice given.

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Student