Hello Dušan
I would encourage you to write in English. I have used an automatic translator to look at your pages, but such machine translation may not convey correctly what you intended.
Also note, this is not the right venue for some of the issues you seem to expect.
The main point I think you are missing is that
all the GFDL content is also under a CC-BY-SA license, per
the license update performed in 2009 as allowed by GFDL 1.3. All the text is under a CC-BY-SA license (or compatible, e.g. text in Public Domain),
most of it also under GFDL, but not all.
It's thus enough to follow the CC-BY-SA terms.
The interpretation is that for webpages it is enough to include a link, there's no need to include all extra resources (license text, list of authors, etc.) on the same HTTP response. Just like you don't need to include all of that on every page of a book under that license, but only once, usually placed at the end of the book.
Images in the pages are considered an aggregate, and so they are accepted under a different license than the text.
That you license the text under the GFDL unversioned, with no invariant sections, front-cover texts, or back-cover texts describes how you agree to license the content that you submit to the site. It does not restrict your rights granted by the license. You could edit a GFDL article and publish your version in your blog under a specific GFDL version and including an invariant section. But that would not be accepted in Wikipedia.
You may have a point in the difference between CC-BY-SA 3.0 and CC-BY-SA 4.0, though. There could be a more straightforward display of the license for reusers than expecting they determine the exact version by manually checking the date of last publication.