is the output from a workstation when using ping command the same as a router ping?

Not really. its depends on the router IOS. it maybe displayed slightly differently but basically the information return is the same. eg. TTL,ping reply etc. For example,a router IOS may be written to only display a"ping successful" and not further give you any info.note this is a extreme example which maybe possible as it basically depends how the IOS programmer write his ping command, most router ping commands will give you information similar to pinging from PC.

Not quite. The router ping to the internet will usually be shorter (smaller value) than from the workstation, because the PC has to make that extra trip to the router, before getting out to the internet.

If pinging back and forth between a PC and the router, each device may respond slightly different, giving small differences in ping time, depending in which direction you are pinging...

It should be.