Formerly profitable at NL50 back when it was easier, took a long break from poker and now building a roll from $10.

Same villain in both hands, he seems on the border between competent (as much as anyone at 2NL is 'competent') and maniacal. His stats over a small sample, but enough to make the four times he's 3-bet significant:

VPIP: 42, PFR: 25, 3B: 17, AF: 3.0, Hands: 24

Over the session my stats (as much as one's image can matter at 2NL) are something like:

VPIP: 29, PFR: 26, 3B: 5, AF:

I have successfully 4-bet-bluffed and shown a different crazy opponent with a ~12% 3-bet stat.

Hand 1:
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Poker Stars $2.00 No Limit Hold'em - 4 players
The Official 2+2 Hand Converter By DeucesCracked Poker Videos

SB: $4.55 (stats for SB: VPIP: 30, PFR: 25, 3B: 10, AF: 2.0, Hands: 40)
BB: $5.03
Hero (CO): $4.99
BTN: $6.39

Pre Flop: ($0.03) Hero is CO with J J
Hero raises to $0.06, BTN raises to $0.21, SB calls $0.20, 1 fold, Hero calls $0.15

Flop: ($0.65) 7 5 K (3 players)
SB checks, Hero checks, BTN bets $0.46, SB folds, Hero calls $0.46

Turn: ($1.57) 7 (2 players)
Hero checks, BTN bets $1.50, Hero folds

Questions:
(1) Against only one 3-bet happy opponent I am going to 4-bet preflop, should I do this against two? The stacks are so deep that even against these crazy 2NL players, if I get it preflop I am probably behind. On the other hand playing JJ out of position, especially against two opponents, sucks, and folding is obviously out of the question.
(2) I can see arguments for doing almost anything on this board, especially once the SB folds: check-fold, check-call, check-raise. He's pretty crazy so I'm not as likely to be behind on a K-hi board as it seems -- AA/AK/QQ (and KQ/TT/Kx for him) make up ~30% of his range prior to the flop bet instead of ~60%. Even given the result of the hand I'm not sure that c/c flop is such a terrible line, since I have 11 questionable outs. When he bombs the turn he's expressing a willingness to stack off so he's either extremely crazy or has a real hand and I can fold.

Hand 2:
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Poker Stars $2.00 No Limit Hold'em - 6 players
The Official 2+2 Hand Converter By DeucesCracked Poker Videos

MP: $4.34
CO: $5.00
BTN: $5.00
Hero (SB): $4.30
BB: $0.98
UTG: $7.27

CO posts a big blind ($0.02)

Pre Flop: ($0.05) Hero is SB with K A
UTG raises to $0.09, 1 fold, CO calls $0.07, 1 fold, Hero raises to $0.30, 1 fold, UTG calls $0.21, 1 fold

Flop: ($0.71) 8 5 2 (2 players)
Hero checks, UTG checks

Turn: ($0.71) 6 (2 players)
Hero bets $0.34, UTG raises to $0.68, Hero calls $0.34

River: ($2.07) K (2 players)
Hero checks, UTG bets $1.97, Hero ??

Questions:
(1) Should I cbet the flop? I am likely crushing his range but I am pretty likely to get bluff-raised here so I check.
(2) Should I check the turn? I like the bet here better than on the flop since this crazy dude has less leverage now, but it might still be bad.
(3) Should I call the river? If I'm folding this river, which is pretty much the best river imaginable for me, I should fold to the turn minraise as well. I think when he pots the river here he is (even at 2NL) polarized with monsters/air. How much air is in his range here?

H1
1) It's ok to flat 3way that deep. I guess it's pretty thin/even slightly -Ev to get in pf. Be aware that SB could have AA in his range from time to time.
2) Postflop I would have played same way. You could peel turn too, but you should know more about villain tendencies.
H2
1) Usually yes, but I bet the turn also near 100% when I cbet the flop, just like I do with AA.
2) Yes. I like c/f, but sometimes c/c it's ok against some players.
3) After the turn play, it's mandatory. Besides missed draws and stone cold bluffs, he could valuebet few worst hands(KdXd).