Tbh I think I'd prefer just to check back the flop, especially 3 way. You say SBs continuing range is strong after calling flop but you try and bluff him off this strong range at a limit where people love to just call down so theres some inconsistencies in your thought process.

What range do you put SB on when he calls the flop and checks twice? I would guess that he has a marginal hand (weak ace, a Ten or some sort of underpair). If he had a strong Ace, he probably would have bet river. So, it's a decent spot to bluff.

However, this is very player dependent. Some people will never fold an Ace here.

In general, I don't think there's any real need to bluff with this particular hand. Set-mining is profitable in position, even more when you're multiway. It would be better to select a hand with Kd.

Pretty random flop bet, if u want to get creative rather start betting 22-44 with a diamond, or some Kq jq kjs, then you have abit More equity when called. I dont se any reason to add random bluffs here 3way, when ranges are pretty strong. And you have the natural better bluffs.
As played i would also overbet river probably:D think sb Will bet flushes alot otr and u can credible rep flushes. Its better to have a high diamond or 54s as you would block his calls. But i think he Will bet overfolding here so like the overbet. Just be careful with the flop play its pretty bad

44 with a diamond is a much better choice to bet flop with, especially MW. When you do spike gin (a 4) on the turn, you wont be completing any FD's and they (FD's) will be a part of his range here in this spot.

If I played NL5, I wouldn't try to make people fold top pairs. It's just not in the top 10 most effective ways of gaining winrate list so I think it's just something that one should not focus on at NL5.