8-16 hand, reads are rock solid as I play with these people all the time, so I will give them in detail as they are why I played the hand this way, but of course not sure I did so correctly.

I am dealt in the CO. 10 handed but everyone not noted folded.
Preflop: TAG raises UTG, SLAG three bets, I coldcall three, SB coldcalls three, BB calls.

Both TAG's range and SLAG's three betting range is 99-AA, AJ - AK, KQ.

Question 1: SB will coldcall three here almost everytime with any two, he is that kinda player, but probably fold if I fourbet. SB and BB are both weak easily readable players postflop and are calling stations that pay off, although SB does like to CR.
I decided to let them both in to make a multiway pot with two weak players in postion. Probably correct with AKs, but what about AKo???

Flop:
Checked around to me, I check.
Question 2: I check here as there is no way I am ahead, and SB and SLAG are both frequent checkraisers, maybe I'll pick up a backdoor draw or an A or K. Anyone bet here?

Turn:
SB leads out, BB/TAG/SLAG all call, I call

I called strictly for my gutshot draw as the pot I think is barely big enough to support a 4-outer but I do have implied odds as well if I hit.
Question 3: This is correct right, I will tell you that the SLAG bitched for 10 minutes that I called the turn after the hand was over.

River:
Checked around to me .
Question 4: Bet this? What if I am checkraised - note that as mentioned before SB and SLAG both like to CR - or take the free showdown?

Bet the river,

I know you are ahead.

This is an interesting hand. I have to tell you guys though, i am not worried about a CR. A straight and a flushie both got there, and they were both really obvious. I think the VAST majority of players wont go for a checkraise in a spot like this, because there was way too much of a chance that itll whiff, since the boards so scary, and also, even if it does work, there is good chance that it wont get paid off anyway, again because of the board. I dont fear river checkraises in spots like this that much, except against real donks...

However, that doesnt mean i bet the river, cause even though i dont anticipate a CR that much, i also think you could be beat too...if these guys are aggro they may have bet/folded 2 pair hands, especially MP guy...I think QK or a set may bet/fold there...tough hand...

I think betting and checking are real close, and in situations like that, i will usually bet.

I agree about a check here, nothing is going to call that you beat and not much that beats is going to fold, I would happily check this here rather than try and squeeze the tiny bit of value you may gain here.