Orange Sherbert & Bubba Kush DWC u Soil

Yes, that's absolutely sufficient for the stage. Your plants also look perfectly fine - otherwise, they would have that stretchy growth and look much more spindly if the light were too low. Being too close to the plants and thus having too much light can definitely go wrong quickly. Cannabis seedlings have only a low light requirement. Their new leaf tissue can be easily damaged by excessive light or heat. Later, when the plants are stronger (I would say, 3-5 nodes with "proper" leaves), you can reduce the distance to 40, then they can handle more light too.

When I run hydro I stick with my basics, no need for extra additives. Mostly it's just important to keep your tank clean. It's not uncommon at all for your pH to change in the first 24 hours. Without going into a long explanation, it's because your introducing more oxygen to your water so your lowering the CO2 levels. Temp in your reservoir is a factor too. These things affect pH. I will generally adjust my pH a few hours after a tank change to accommodate this though you could also try to recreate your reservoir conditions when you mix a fresh batch.