Jose Luis:
I can help with questions 4 and 5.
I would not change mounts that were installed in 1998, unless you see something wrong with them; I believe they last lots of years, maybe 10.
The website for the hose supplier is
www.aircrafthose.com. I have used them and they are very good. Impress on them the problem with returns, so that they'll check them twice.
You raise some good questions on engine overhauls and cylinders, and I hope GMAs or others can provide answers.
Saludos,
Ernie