Hi JM,
Since this is for professional use I will give you some tips warning straight away.
-WiFi or cables: use LAN cables as much as possible. It will save you a lot of trouble and they work when you need them.
-Repeater: If you are going to use a repeater use a new one. Older repeaters are usually rated for a channel of 56 Mbit/s. Two-way communication makes it 26 Mbit/s theoretically! Distance, walls, … makes is much less very quickly. Use LAN cables if possible.
-HD cams: 720p, 1080p or 1280p use a lot of bandwidth on the network. Depending on number of cameras use a GBit LAN. Most equipment is for GBit today.
-Cameras: NCS support Pan-Tilt via pre-formatted template or by ONVIF Standard. When it comes to optical zoom in the camera it is trickier. If it is in the pre-formatted template it support it, but ONVIF zoom might be not so easy. NCS console and windows client support digital zoom.
-Infrared cameras: The IR LED´s are usually located around the optical arrangement. IR attracts a lot of bugs, bats etc since they see that light. If that will be a problem there are a lot of external IR sources on the market to put where you need them.
-CPU power: if you have many HD cams and are using motion detection or continuous recording it usually consumes CPU power.
-HEDEN cameras: NCS have some pre-formatted templates with PTZ and hopefully some will fit your model.
Start slow and test and you will discover what works and not in your system.
Good luck,
-Henrik