Great post and summary. To answer as best I can (I wrote a big thing that goes into more detail I'll get after its edited to be more well-written);
1) Eventually, yes.
2) We will adjust those to new mechanics or wrap them up into similarly-powered stats. Jax utilizes it for gameplay decisions, while on Udyr it's more about the damage reduction and power of it than a gameplay decision. Case-by-case approach.
3) Since this has been the plan, removing dodge (and therefore Nimbleness) is a piece of 1). Nimbleness was a cool mastery - if dodge was staying, we'd have left it.
4) We will be doing something to make this right for players. Details to come, but our plan is specifically about making you guys happy in this regard.
Lead Champion Designer