It seems like pretty easy job, as a skilled IT administrator having more than 7 year plus experience I am sure about that. I am a new freelancer so i will my best, you can pay me if you are satisfied only.
Regarding the approach:
Please consider following points, I breaking down to make more sense to you.
1. I will setup up the pfsense for blocking streaming services, porn sites and other not productive services.
2. Create a traffic shaping for VoIP services for smooth run.
Looking forward to work with you.