Just because, here is my standard PSA on soil compaction
You cannot just "put in dirt and compact it really well" even if you are using the correct fill material, you cannot just "compact it really well". Soils have a optimal moisture content (percentage) where they will compact to their maximum dry density. If you have more or less water in the soil, you can compact it until the cows come home and it will never reach its maximum potential density. Then 2 years down the road when it dries out some, or it rains and it gets a little wetter, with your pool sitting on it, it compacts some more. No bueno.
Some soils are more forgiving than others. The goal in construction (most of the time) is to reach 95% of the maximum dry density. Some soils have a flatter curve. What that means is that if your moisture content is between say 4% and 9% you can still hit that 95% compaction. Other are really sharp, and if you are more than a 1% off you will never reach 95% compaction.
So how do you know these curves and measure the compaction? You hire a geotechnical engineer (sorry, I left that field a long time ago and no longer do site inspections). They run compaction curves (Proctor tests) in the lab and then measure the in place density in the field.
Now we come to point #2. Isn't that a lot of overkill you say? I'm building a pool, not a garage. Ahh, there is the difference. A pool is HEAVY. More psi loading than a garage. Also, a garage on a slab is much more rigid, and is able to bridge minor variations in the substrate. An ABG is a big flexible bag of water with almost no structural rigidity. If something starts to settle, the whole bag o' water is going in that direction, with disastrous results.
Now, you are doing 1" lifts, which is a good start. Hand compaction is next to useless. Plate compactors depend on the unit itself. If you don't need your machine to lift it out of your pickup/trailer it likely is not enough.
You said you added lime. Lime is not lime is not lime. Quicklime, hydraded lime, and hydraulic lime are all different, behave in different ways, and have different properties when it come to ground modification. They should also be worked into the soil, with something like a sheepsfoot roller, not sprinkled on top. If you are trying to compact clayey soils, a sheepfoot roller is your best option actually. Plates and smooth drums are a distant second.
You also mention mortar dust. Are you just adding bags of mortar to the ground? Again, like sand, mortar is not mortar But, all mortar is sand, cement, and hydrated lime. It is just the ratios that make it different. You are not getting any strength from the cement by sprinkling it on. It is too thin a layer, and doubt it has hydrated properly. You would have to be adding a lot of mortar mix to make any difference