Mostly, you can do what you want with pfSense.
*) Splitting the bandwidth: traffic shaper
*) Monitoring content: yes, packages available to do that
*) Who's accessing what tied to Active Directory: I don't think so.
*) Wifi via MAC address: MAC addresses are trivial to change, so access via MAC address is about as effective a security strategy as posting signs saying "Please don't hack me"
*) Other Wifi stuff: Yeah, you can do Radius authentication to an Active Directory
*) PCAnywhere from out in the Internet - yes, you'll probably want to look at OpenVPN
For more details, RTFM. (Or spend some time reading the individual tech forums (EG: OpenVPN, Traffic Shaper, etc)
Good luck.