1)Yeah the 416 arms and uprights should fit. I think the 417 has revised uprights? Can someone else confirm.
2)A difference in each block is 0.5 a degree. Best to just look at a chart.
http://www.petitrc.com/reglages/tami...ckSettings.pdf
So your rear toe will be 3 degree, drop to a rear A or B block to get 2 and 2.5 degrees.
3) Tamiya 54137 has 1 degree but its aluminium. I dont know of any plastic or carbon ones.
4)The white hard spring set includes springs from the original red to white hardness, the white springs your getting will probably have dots on the tops telling you what they are.
Check the chart:
http://www.petitrc.com/reglages/Univ...pringChart.pdf
5) No the 416 diffs are a different width, Spec R is the only gear diff for the TA05 that I know of.