5c/10c PLO8 8 handed

SB $10.00 A645
CO $16.47 A42K

MP open limps 10c
CO raises to 45c
BTN calls 45c
SB calls 45c
BB calls 45c
MP calls 45c

$2.25 in the pot

flop was J32

checks to CO
CO $16.02 bets $1.12
BTN calls $1.12
SB $9.55 calls $1.12
BB & MP fold

$5.61 in the pot

turn was 3

checks around

river was 8

SB $8.43 bets $5.61
CO $14.90 calls $5.61
BTN folds

$16.83 in the pot

SB takes $11.93 after rake - nut low & nut flush
CO takes $3.97 after rake - nut low & 2 pair

Questions:

Considering the notion that a player should strive to win the most / lose the least amount of money in every hand involved... when you're almost certain you're only getting a quarter of the pot, is folding an option? In the example above, CO would've obviously lost less had he folded to the river bet, but if he's folding nut low there, what does that say about the player? Are we ALWAYS calling the river regardless of other information available / known to us? Can we even consider that a leak?

BTW I was SB Should I have lead turn? I was thinking if I lead turn I can bluff most rivers, but LMK what you guys think. Thanks!

Folding the nut lo on the river is sometimes correct.

How is SB not putting all the money into this pot?

Folding nut low is possible, but I'd say folding A24x here is just bad. It's a hand that is more often quartered than quartering certainly, but also splitting quite often. I can't see a way getting 2:1 folding should be even seriously considered.
No, leading turn would be absolutely horrible. You are turning a decent hand into a bluff and your hand has the worst possible blockers (you have the type of hand you wish your opponent would have).

You should c/r flop though, especially after a bet and a call. Hand will have good equity anyway and them folding is a brilliant result.

I'd also give serious thought to trying to c/r river. Edit: hmm, guess not with these stacks, though still it is interesting. Most hands that call your bet will bet when checked to.