Just trying to ease myself back into poker having taken a bit of break from grinding, starting afresh and trying to get things done right this time around. I've pulled up four hands from a recent session that I wasn't certain about and would love to know your thoughts on how I played them, thanks.

1. Flop a full house, I checked the turn thinking villain may take another stab, or would possibly catch a flush on the river - not sure if this was the right play or not, his miniscule bet threw me on the turn and I thought he probably had a hand and was trying to extract some value poorly, so decided to re-raise here.

PokerStars No-Limit Hold'em, $0.02 BB (8 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop

MP2 ($2.48)
CO ($4.84)
Button ($1.01)
SB ($4.98)
BB ($1)
UTG ($6.68)
UTG+1 ($3.81)
Hero (MP1) ($2)

Preflop: Hero is MP1 with 5, 5
UTG bets $0.06, 1 fold, Hero calls $0.06, MP2 calls $0.06, 3 folds, BB calls $0.04

Flop: ($0.25) 7, 2, 5 (4 players)
BB checks, UTG bets $0.02, Hero raises to $0.24, MP2 raises to $0.46, 2 folds, Hero raises to $0.70, MP2 calls $0.24

Turn: ($1.67) 7 (2 players)
Hero checks, MP2 bets $0.04, Hero raises to $0.46, MP2 calls $0.42

River: ($2.59) 8 (2 players)
Hero bets $0.78 (All-In), MP2 calls $0.78

Total pot: $4.15 | Rake: $0.20

2. AJ on a paired board, my plan was to call and fold to a turn bet.
The open raiser was 52/16 over 50 hands, and the caller was 34/10 over same number. Having doubts in hindsight about if I should be playing this from the blinds.

PokerStars No-Limit Hold'em, $0.02 BB (7 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop

Button ($2.26)
Hero (SB) ($3.87)
BB ($0.83)
UTG ($2.94)
MP1 ($1.29)
MP2 ($0.94)
CO ($1.97)

Preflop: Hero is SB with J, A
1 fold, MP1 bets $0.06, MP2 calls $0.06, 2 folds, Hero calls $0.05, 1 fold

Flop: ($0.20) K, A, K (3 players)
Hero checks, MP1 bets $0.08, 1 fold, Hero calls $0.08

Turn: ($0.36) 10 (2 players)
Hero checks, MP1 checks

River: ($0.36) 4 (2 players)
Hero checks, MP1 checks

Total pot: $0.36 | Rake: $0

3. 78(s) from the button, with a flush draw. I thought the donk bet looked really weak and when they both checked behind on the turn I thought there was a fair chance they were chasing a FD or had very mediocre holdings so decided to bet hard knowing I still had a chance of catching my flush on the river.

PokerStars No-Limit Hold'em, $0.02 BB (9 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop

SB ($2.93)
BB ($8.14)
UTG ($3.51)
UTG+1 ($4.76)
MP1 ($1.28)
MP2 ($4.27)
MP3 ($4.80)
CO ($1.80)
Hero (Button) ($3.84)

Preflop: Hero is Button with 8, 7
2 folds, MP1 calls $0.02, MP2 calls $0.02, 2 folds, Hero bets $0.12, 2 folds, MP1 calls $0.10, MP2 calls $0.10

Flop: ($0.39) 10, 2, 3 (3 players)
MP1 checks, MP2 bets $0.06, Hero calls $0.06, MP1 calls $0.06

Turn: ($0.57) 4 (3 players)
MP1 checks, MP2 checks, Hero bets $0.50, 2 folds

Total pot: $0.57 | Rake: $0

4. AK misses the flop in position with two callers. Was my Cbet ok? I didn't think he was likely folding to a double barrel after calling the flop c-bet, so didn't double barrel, was that correct? Small bet looked like a value bet to me on the river, holding Ace high, an easy fold?

PokerStars No-Limit Hold'em, $0.02 BB (5 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop

BB ($1.57)
Hero (UTG) ($4.09)
MP ($1.27)
Button ($2.87)
SB ($1.31)

Preflop: Hero is UTG with A, K
Hero bets $0.08, 2 folds, SB calls $0.07, BB calls $0.06

Flop: ($0.24) J, 9, 6 (3 players)
SB checks, BB checks, Hero bets $0.18, SB calls $0.18, 1 fold

Turn: ($0.60) 5 (2 players)
SB checks, Hero checks

River: ($0.60) 8 (2 players)
SB bets $0.28, Hero folds

Total pot: $0.60 | Rake: $0

Thanks for the feedback all much appreciated!