So you are switching from bottled water to your well water? I wouldn't switch 50% at a time. I would do more like 20% a day, so the fish can adjust to the new parameters.
There is no ammonia because the cycle is semi-established... just got to get that nitrite down to under 0.25. It probably won't take too terribly much longer to get the tank cycled.
For the temperature - when you do your PWC
, just match the temp as close as you can. If the water is off by a lot, the sudden temp change can kill your fish.
The pH reading is interesting, but I wouldn't worry about it till your liquid test shows up.
When you settle into your maintenance routine, keep the nitrates below 40.