Soil

It’s always good to add new soil every couple weeks give the plant a little boost

compaction happens. Sshould have some limit to how far it can compact. It doesn't matter at this point if you add more. If it makes you feel good, sure. Those exposed roots no longer function as roots at this point, so covering them isn't going to do much. Don't cover up too much exposed trunk as a constantly wet trunk is a foothold for pathogens. you can tamp down a bit more before potting up / planting the seed. This will compress the substrate slightly -- definitely don't over-do this. I don't try to compress. I justmake sure there are no air pockets that will collapse later. You can also water more slowly, which will slow/limit compaction a bit. but over time, this is somehwat inevitable but you can mitigate it and it's not too big of a deal. If you cover the exposed roots up ASAP before they differentiate into stem, you'll save them. If you have a tone of roots in that top 2" or so, it's indicative of poor watering habits. You are training superficial roots if this is a problem. 1) fully water appropriate to method 2) wait for approriate dryback and repeat. keep it simple. This keeps roots growing downard toward consistently greater moisture. Roots turn toward greater moisture.

yes definitely. i like to add soil and worm castings along with my next feed. Definitely worth it.

100% Sometimes your soil isn't packed properly, or your plant eats it up, and such. Roots + light = bad