Preflop sizing is 100% dependent on your standard raise here.

The river is too late here imho to get him off a hand that beats us.  Maybe if he has like K2 or something completely random, but other than that he is folding everything we beat and calling everything that beats us.  The decision between c/c and c/f is interesting, but Ill wait until you finish the question regarding your decision(which imo is a pretty easy check).  I guess in some crazy worlds c/shoving seems fun, but meh.

The flop however is interesting.  I think we should be folding or shoving(I wavered between just 3 betting or shoving, but I think shoving is better).  But betting isnt a standard for me at all here.  Checking does have its merits here, especially against people who are aggro, as a c/r prices them out better than a b/r(when we get raised), allowing us to get slightly better FE(assuming his bluffing tendencies are the same).

The main reason I think shoving is acceptable here is because I dont expect him to have nuts(aka any straight) or 54 enough here to scare us.  I dont expect 2pr-sets here often with the mni raise, and 2's, 3's are not a huge concern.  I guess %x is somethnig to worry about but we have decent outs against all but 56 and a5.  Like one of the above posters said I agree that his range is weighted towards 4x and flush draws or air.  So shoving seems fine.

In fact after typing all of that up, we can probably get away with a 550k re raise on flop.  Not many hands I see changing their decision toa  3 bet as opposed to a shove, except maybe a 4x makes a bad call against us allowing us to make more.  We are effectively priced(I think didnt do the exact math) in once we do this, so his 4 bet bluff range isnt a huge concern.