1. For your situation about colonization, you did the right thing, even though the populations are low. Grabbing the planets is the hard thing, letting the population grow is easy. There are some techs, they are green in color that can raise your Population Growth skill. Also, morale helps tremendously in growth. Without looking it up, I think it's 21-40% no additional growth, 41-74% +25% growth, 75-99% +50% growth and 100% +100% growth. So it's advisable for you to lower your taxes until all your planets are at 100% morale. You'll run a deficit for some time, but eventually taxpayers will balance it out. This magic number is around 2b on a planet. None-the-less, run 100% morale for as long as you can, or until all the planets are maxed in population. Also to note, low quality planets will have a cap on them for how far they can grow. For example, a PQ 4 planet is capped at 2.5b for growth. Now, you can still ferry people over to the planet to it's true cap with either troop ships or colony ships.
2. I'm not at my gaming PC, but if you go to the planetary level for a planet and then in the bottom right there is a Planetary Details button or the like. It's either that one or the one next to it..
2.5. Soldiering bonuses would be universal, the hp thing would be just that ship. I'm not sure of a place you'll jsut see what came from anomolies, but you can see your stats on the Stats and Graphs section.
3. Check out this wiki page https://www.galciv.wikia.com/wiki/Logistics
Overall that wiki site will answer a ton of your questions. Some of it will be outdated, especially if you are playing TA.
