NL2 FR - Full house in freeplay pot

Hand converted with online PokerStrategy.com hand converter:

Play hand

$0.01/$0.02 No-Limit Hold'em (8 handed)

Known players:
[tg]MP1$1.81:///////;MP2$2.34:///////;MP3$1.44:///////;CO$0.56:///////;BU$1.50:///////;SB$1.95:///////;BB (Hero)$1.97:///////;UTG2$1.80:///////;[/tg]

Preflop: Hero is BB with 3:c, 4:h.
UTG2 calls $0.02, 4 folds, BU calls $0.02, SB folds, Hero checks.

Flop: ($0.07) 4:d, 3:s, 4:s (3 players)
Hero checks, UTG2 checks, BU checks.

Turn: ($0.07) A:c (3 players)
Hero checks, UTG2 bets $0.05, BU folds, Hero raises to $0.10, UTG2 calls $0.05.

River: ($0.27) 2:s (2 players)
Hero checks, UTG2 bets $0.26, Hero raises to $0.66, UTG2 raises to $1.68, Hero calls $1.02.

Final Pot: $3.63.

I definitely played this wrong but luckily it worked out anyway. Not really sure what to do in this kind of situation though, obviously i'm well ahead on the flop but there's flush and straight draws out there that I don't want to scare off so I opted for some slowplay. Then a minraise on the turn to try and represent the ace but still give him good odds to draw for a flush or OESD. Nice card for me on the river as flush & straight draws both completed, only A 5 beats me here so obviously i'm going all in - hopefully he still thinks i'm only holding aces.

So is slowplay the right choice here or should I be protecting against higher PP's making a better FH? At what point do I start betting bigger to get me more value if draws don't complete?