Yeah, truthfully, pH isn't that important. most fish can adapt to a different pH as long as it isn't too far out of their preferred range. I believe they prefer to have a pH of about 6.8-7.2
Yep. Seashells (at least real ones) can cause the pH to spike. So, If you've already taken it out, I would recommend continuing with 1 water change a day, and I would keep adding a little bit of salt every day but stop using the easy balance for now. The reason for this, is we want the pH to drop slowly back down to a stable level. once it stops, check your pH and we can determine if it really needs to be brought up anymore or not.
As far as the water conditioner, I use the same thing. I actually prefer stress coat, simply because it works as a conditioner and as a stress coat. so it can help regrow fins and stuff too. :D As long as it removes ammonia and other harmful chemicals from the water (as aquasafe does.)
Its really good that they get along so well. :)
happy owner of a wild type GFP axolotl named Percival and too many guppies to count.