How do you tow 4wd on a tow bar?

Sure can. Look at those big RV's on the road ... most are pulling a car using a tow bar.

Blue Ox tow bars have special brakets for most cars and an application guide.

No, but you can add one however because they are such small cars they probably wont be able to tow very much.

Yes. Make sure that the transmission is in Neutral and that the transfer case is also in Neutral.

Assuming you're referring to a hydraulic tow bar, those are the hydraulic arms which raise, lower, and turn the tow bar.