Well, the study didn't identify height of drinking bowls as a factor either way. Not sure if that was even examined. But I'd put the drinking bowls on the ground anyway. Really, how long does a dog spend hunched over it's drinking bowl? 30 seconds, a minute? That's no hardship, and for the possibility that's it could be a risk factor, I'd just play safe and keep all consumables at ground level - the way nature intended.
As for the citric acid - yep, it's best to check for that as a preservative and don't pre-moisten those foods. Not all food manufacturers will admit that it's a problem (have known one to deny it flatly, but then state that they were removing citric acid from their food for entirely unrelated reasons LOL), and continue to recommend that their foods be pre-moistened.
We shouldn't think that citric acid is "bad" though - it's not. It's a perfectly good, naturally occuring preservative that I'd far rather see in a food than the nasty chemical preservatives like BHA, BHT or ethoxyquin. But you just don't pre-moisten those foods that use it as a preservative, that's all.