1. Is there a way to make
ftp://mydomain.com a secure site so that only auth. users can see the files?
I realy hate to say this, but have you actually looked at the server manager page, and tried a few things under Information Bays, like enabling public access via FTP?
..and if that does not do what you want, why not??
2. What is the path of where the users are in my server when they FTP ..
/home/e-smith/files/ibays/whateveryoucalledyouribay/files/...and your files go here..
And if I miss something because I did not read your earlier posts, forgive my ignorance, I just have a 5 min break and spotted your question, to which I have the above answers.

good luck
kees