98 Malibu A/C and fan problems: more feedback needed

I have read many of the threads regarding the problems with the Malibu: I admit finding comfort that there are answers out there and discouragement that I could have more problems later!

I read the thread 324040 regarding the HVAC Blower fan and need more feedback to see if my problem will be fixed by this solution:

When I bought the car used, I received no air flow from the upper vents and only air at my feet (regardless of setting). This was fixed by replacing something in the dash by a Chevy dealer.

My A/C has been intermittent for a long time and thought it was fixed when I made 2 alternator replacements. It wasn't. My Questions:
1. Many people report the intermittent problems with the A/C. Are there any solutions except replacing?
2. My fan blower is also intermittent: sometimes it works fine, then later I can feel no air coming out of the vents. The fan is making a noise at all settings from 1-5 like it is blowing but the sound is different:When I crank it up to 5, it is making a louder, muffled sound but still only blowing puffs of air. Later, all will be fine. BTW: This can happen with or without the A/C failing. Is this the same problem that will be fixed by the thread 324040?

Thanks!