[kamocat]

You can get the current information in any mode, though it is only accurate within an Amp.

Regular RJ12 cables, like the one you've linked to, can be used to connect the Jags and the cRIO together. Between the Jags you actually only need the center two conductors, but I would recommend making all your cables with 6 conductors so you can swap cables around if you need to.

I'm assuming the document you're referring to is the Getting Started Guide. Yes, you need a termination resistor on both ends of the network. You can use a 100 ohm or a 120 ohm resistor. Make sure to build it in a way that the leads of the resistor will not short together.
Granted, I have gotten CAN to work with only one termination resistor. However, the CAN spec calls for two, so I would use two. You do not want to introduce additional points of failure into the system.