Interesting about the dreams, when I was younger, taking just Magnesium Oxide with some pyridoxine (B6) was my cheap bedtime stack and I had some erotic nightmates, heh heh. Yeah though ZMA is an excellent product.
I don't personnaly see the benefit of Amino Acids tablets. These things were popular in the late 80's and early 90's with lifters munching handfuls as they went about their daily business.
I'd looked at some of these whilst doing my Food Science Degree and they were bound with loads of dicalcium phophate. DCP in its most basic form was made up of limestone and phosphates and used in animal feeds, including the amino acids (many D form) given to pigs, goats, sheep etc.
By taking lots of Amino acids tabs bound with DCP and other bulkers/binders you can end up ingesting too much Calcium which in the least can lead to constipation and possible more. Plus Calcium inhibits the absorption of other minerals in certain circumstances such as Zinc.
You gotta remember when Amino Acid tablets were popular, protein powder was not so good. Whey was in its infancy (as a decent supplement) and most PP's were full of Soy, denatured Caseins and IPP or Isolated Pea Protein to you and me.
In other words, they sucked ass.
Since Whey, decent Caseins and things like undenatured Egg albumin powder blends are out there, there isn't much need for chewin on amino acid tablets.
However, taking Branched Chained Amino Acids, Iso-leucine, Leucine and Valine during workouts allegeedly helps stabilise blood sugar and aid in elevating growth hormone. I can't comment too much as its not my area though.