I think if you have a fish eater with the sally lightfoot, I think you have a decision to make as it will likely keep catching what it can. My personal favorite yellow fish is the yellow fang blenny/canary blenny.
BTW- This is the exact type of question the Fish Finder is supposed to help us with. We just need to get more members to input their fish to make it a useful resource.
If you have too small of a tank for a yellow tang, I would go with a Midas Blenny, they are VERY cool to watch and not as "hiding" as other blennys they hang out in the open swimming around, very active.