vkaryl, thanks for taking the time to share a first approach for us to work on :)
First problem will be that your static pages are .htm or .html, and wp is built on .php pages...
Second problem is (...) to recreate .html files into .php files which are valid XHTML.
At first look, and acknowledging I'm a newbie, it seems to me that both issues are very close in that the main challenge is to change from htm to php, so that wp can generate valid xhtml; is that true?
I also would like to know where does wp takes content (for example text) from? Is it a database? Is there a way (maybe a plugin) to import data from html (or other formats) to such database?
Logical sequence: set up a "sister site" using wordpress, and rework your files little by little so that the sister site will eventually look and work like your original site, but built on wordpress.
I agree with you in setting up a sister site to do all the job ;) and then the main issue would be to find a fairly simple way to rework the site from htm to php... what do you think?