the steering wheel is the same as the 4runner so you could swap them. I almost did before the 2012 came out when I had to replace my airbag. Its uses the same circuit for the steering wheel controls as well. You could probably find a used undeployed 4runner wheel and airbag on ebay.
Also, I am pretty sure the nav unit will only swap into the tacomas with JBL. I have looked at the wiring diagrams for the 4runner and I would bet my truck the new nav system is based off the 4runner which uses the separate amp just like the JBL tacomas.
but a 2day pass to toyota's TIS and you could know for sure about the radio. that is if anyone has $15 they want to sacrifice.