SB is basically always a fish, I don't care what stakes we're playing.
Him being in the hand, yes I think value betting is +EV because of the added equity (especially since we have position on him).
Purely against UTG... hmmm, his range for bet/calling pre-flop against reg BB... 88-JJ? I can't give him a range any wider than that unless he's using reads (i.e. if he thinks you're spewy post-flop there will be dominating hands in there as well, if he thinks you're a TAGfish there'll be some A's in there). Still, the vast majority of players wont be adjusting very well (not just at 4nl) and I'd just go with 88-JJ and we're behind that, I also think the TT/JJ in his range is more likely than 88/99 which hurts us more.
We can maybe add in AQs just to represent the random stuff that happens, since occasionally people will be acting on reads when they shouldn't, or they're not as good as we thought or they misclicked pre-flop or something. It's certainly calling the flop once it gets there, and brings our equity back to 50/50 (I'd still check-fold, I'm just illustrating that as soon as we add SB into the equation it's an easy value bet). - I used AQs because it has decent equity and most random stuff from decent players has decent equity. It's also only 4 combinations to represent that it's uncommon.
Hope my semi-mindless rambling makes some sense..