Nagios support questions

I am looking at Nagios as a solution but I am not sure it meets some of my requirements. I am looking for a tool that does more than just monitor the servers and infrastructure.
Is there a way to use Nagios to power on and power off Windows and Linux servers gracefully? I need to be able to shutdown and restart the servers at specified times or manually from within the tool without having to RDP or VNC or remote KVM to the server. The full requirement is to create a group of servers and power them all down or on at the same time. Is this possible??
Can you use SNMP mibs to access PDU ports that control the power ports?
Can you implement Cacti or MRTG graphs within Nagois or use features already included to monitor network utilization at the server level and at the switch level? Fibre Channel traffic across switch ports would an added plus.

Thanks sorry if I posted these questions in the wrong area.

Why you need Nagios for this? Do you want them to shutdown/restart after some incident monitored by Nagios?

You can use SSH to shutdown/restart servers. In Windows you just have to install ssh-client to host. You can also define the script which has to be run after alert in Nagios.

Is this what you meant?