PLO interesting hand

[msk]

I watched an interesting hand last night online in a PLO 2/4 ($400 buyin) at Paradise (44% avg preflop).

MP (about $380, agressive player) raises to $8, three callers, then called by SB (with about $180) and BB. 5 players in for $40.

Flop is K [img]/images/graemlins/spade.gif[/img]Q [img]/images/graemlins/diamond.gif[/img]J [img]/images/graemlins/club.gif[/img]. All check. I am surprised. Come-on, someone has AT, someone else has trips. Ok.

Turn is 4 [img]/images/graemlins/diamond.gif[/img]. SB bets $40 (pot), fold to MP who raises to $80. All otherw fold, SB re-raises, and then MP reraises SB all-in.

River is K (no flush). MP wins with JJ [img]/images/graemlins/diamond.gif[/img]T [img]/images/graemlins/diamond.gif[/img]9 for a fullhouse. SB had AAT5r for flopped straight. (5 might be wrong, but a rag).

Ok, now that we know the cards, what are the correct plays?

1. Should SB bet the pot on the flopped nut str8, with 4 players to follow? And likely trips (and possibly two pair also) out there? (but no flush looming).

2. Should SB bet the turn, which misses making a possible FH, but makes a 4 flush? Or should SB wait for a safe river?
(Maybe call the pot bet on the turn and give up if losing the nuts on the river to a paired board or another diamond?)

3. Should MP go allin with the SB on the turn, which gives the MP about 10 FH outs and about 7-8 flush outs, none of which are the nuts? Even I knew by now that SB has the AT, but they could have included the A [img]/images/graemlins/diamond.gif[/img] and another [img]/images/graemlins/diamond.gif[/img], killing MP's outs....

Did they both play this really badly?

What are the correct plays for both players?

Thanks for your thoughts,

Mark