I would suggest you raise your pH first - it may be lower than 6.8 since that is usually the lowest reading on the scale. Low pH can damage the liner. Once you get the pH up then you bring the alkalinity up. I believe 80 to 125 is the recommended range for alkalinity so you're not far off.

As far as the CYA, the higher it gets, the higher the chlorine level you will need so if possible, try to keep it between 30 and 50. The tri-chlor will raise CYA so you shouldn't need to add any more at this point but keep an eye on it to get an idea of how fast it is going up.

Yes, you can add all of those through the skimmer. I usually add the bleach in front of the return jet but others on the forum add it thorugh the skimmer.

Peter