OK everybody, I need some advice!

Have a 1920's, top-of-the-line, old house that is plastered
throughout.  Six years ago, some patching and cutting in was
done in various places, and we used drywall mud and plaster
of paris.  All the work has failed.

There is no one left in our area that can work with real
plaster on lathe.  A contractor I know told me the walls had
gotten wet (true), and "re-activated the lime"...... is this possible?
If this is so, once the wall is done, how can you ever change it?
He said I could only paint with oil base paint, but that's what I
used the first time around, and it is still peeling and the plaster is
chalking....

So.......
a)  what do I use to patch or skim coat ?
b)  how do I do it without "re-activating" the surrounding areas ?
c)  what the heck do I paint with when done ?
d)  any reading or viewing materials you all can recommend?

I would hire someone gladly, but as I said, there isn't a plasterer
left in the area,  the last one having committed suicide two years ago....
I swear it's the truth !

Deb Bledsoe