The Interface Traffic will get you bandwidth/utilization information and the Net_Connect Probe can capture availability, the SyslogGTW and LogMon Probe will get you alarms so you really only need the SNMPGet Probe for performance stats like CPU, etc.
The SNMPTD Probe will get you traps/notifications too but most of that will probably be generated from syslog too so you may run into overlap.
Dustin