AQo TPGK on dry board OOP SB vs MP

Here comes another hand I might have messed up

$0.05 NL (6 max) - Holdem - 6 players

BTN: $5.67
Hero (SB): $5.02
BB: $7.64
UTG: $7.23
MP: $10.24 (VPIP: 6.52, PFR: 4.35, 3Bet Preflop: 4.00, Hands: 47)
CO: $3.93

Hero posts SB $0.02, BB posts BB $0.05

Pre Flop: (pot: $0.07) Hero has A♣ Q♦

fold, MP raises to $0.15, fold, fold, Hero calls $0.13, fold

Flop: ($0.35, 2 players) 5♠ 5♣ A♦
Hero checks, MP bets $0.18, Hero calls $0.18

Turn: ($0.71, 2 players) J♥
Hero checks, MP checks

River: ($0.71, 2 players) 3♦
Hero bets $0.34

Thoughts:

preflop:
As preflop-range I give villain:

77+, AJo+, ATs+, KQ, KJs+, QJs-87s

flop:
For his c-bet OTF I give him all his Ax combos as value-bets and his broadways with both backdoor-flush- and backdoor-straight-draw potential (which also block some of my Ax) as bluffs. I think a call is a must, as I am still ahead of most of his range.

turn:
He gets to the turn with:

combos which beat me:
AA (1)
AK (8)
AJ (6)

split-pot:
AQ (6)

combos I beat:
KQs; KJs; QJs; JTs (other than hearts; 3 + 3 + 2 + 3 = 11)

After his checkback I see him only left with the combos I beat.

river:
The card is a blank. I think I can attempt a thin value-bet here. 8 of his 11 remaining combos contain a Jack. I think he sometimes would call with them.

but then:

River: ($0.71, 2 players) 3♦
Hero bets $0.34, MP raises to $1.25, Hero ????

I really didn't know what to make out of this raise. Of course I didn't have it as detailed as here, but during the hand my thoughts till this point had more or less the same conclusion as what I wrote above. So his raise can only mean two things: Either he is shamelessly bluffing or I made some grave handreading mistakes. I ended up with a suicidal call already assuming that he had slowplayed AA or AJ, still hoping it might be a bluff.
Looking back I am still not certain if I should have folded here. I guess his nitty stats suggest that he probably wouldn't be bluffing all too much. On the other hand the sample size is quite small and he didn't really represent a value-hand.
That's what he ended up showing:

Although it really surprised me and I still think villains c-bet OTF was not a good play by him, his slowplay OTT made me pay him off in the end and as he really didn't have to fear anything from my side, he probably could afford to not bet the turn. I don't know if he played this very well or very badly. He had 20/15 stats on me at this point.

Questions:

1. Do you think the ranges I put villain on are realistic for most situations (flop/turn/river before his raise)?
2. How would you have played the river? bet/fold? check/call? bet/call?
3. Should I usually assume, that people slowplay a certain percentage of their strong value-hands like this?
4. What do you make of villains play in general? His c-bet OTF? His check OTT? Can it be advisable to play like this in certain situations?