I would wait the full 48 hours. Most likely it needs it to cure and any dampness will prolong it from curing. I cant tell you for sure if it toxic, but my guess is it is until it cures. HTH
If its 65watts that would be low lighting and approx 2 watts per gallon. You could probly get away with keeping mushrooms. They may not thrive but they will live.
Using buffer. I use Kent superbuffer. You will need a test kit and you also do not want to dose alot at once. When I dose I only add 1/2 TBS to my top off water once in a day.
Yea I would move the emperror over to the 25 and you should be all set. If you do that feed the 25 a pinch of fish food every other day for a week and test your water for ammonia. If 0 ammonia you should be all set.
Yes you can do that. What I mean about bio media is the stuff that is in your filter on the 25. Bio media is like little pebbles and cyclinders. What kind of filter do you have for the 25?
Cycle it with a cocktail shrimp. If your 46 is cycled you could put some bio media from your 25 in there to get the bacteria to frow on that for a couple of weeks then just pull it out put in the 25 filter and should be good to go.