Are the PD rules exactly the same for the retypesettings?
Retypesettings are under the same general rule regarding the source material used. A retypesetting (or re-engraving, to use the traditional term), is protected for a minimal term in some EU countries (25 years from publication in the UK, for example). The question has not been directly addressed in US case law, but the Supreme Court decision
Feist v. Rural would be a significant factor in arguing they are not protectable under US law because they lack sufficient contribution by the person who created it to pass the "threshold of originality." Canadian law (which IMSLP operates under) is similar in this respect to US law in that a fairly high standard of originality is required for something to qualify as an "adaptation."
IMSLP treats a retypesetting as a potentially copyrighted item if it is less than 25 years old. For example, we will delete items posted form the Werner Icking Music Archive posted here without the express permission of the editor/typesetter - more as a courtesy than because we think that such items are protectable under various copyright laws. If you post your own new typeset, we request that you list yourself as "editor" (since a certain amount of editing is unavoidable) and as "publisher" (since posting a file on IMSLP constitutes "publication" under a number of copyright laws), under one of the Creative Commons Licenses.
Are the PD rules exactly the same when the ressetted sheet music is provided from a public place (In my case the Music Library of Sweden).
As for the Music Library of Sweden, it might be a different case if the library has itself posted the retypesets for free, unrestricted download. Unlike WIMA or other online archives, the Music Library of Sweden is a State-funded entity, so different rules might come into play. Specific examples would be very helpful. I would consult with my fellow copyright reviewers so we can have a policy about their retypesets.
Can I make a non PD (if the composer is PD in EU since I live in Sweden) edition suiteble for this page by taking away editors addtions (slurs, accents, wedges, dynamic markings and so on . . .)
As a general rule, yes - as long as the work itself is PD. This can be tricky in some instances if a given work was never published until recently, though.
As for the Albinoni editions by Kneusslin and Giazotto, the crucial question to consider is: What has the editor added? If a continuo realization has been added, they are most likely protected for the editor's lifetime plus 50 years in Canada, 70 years in the EU. If the edition is an urtext-style edition where the editor's contribution is chiefly correction of errors by comparison of primary soucres, the edition is protected for a very limited term in many EU countries (no more than 30 years from publication, only 25 in the UK and Germany, 20 in Italy). IMSLP is observing a 25-year courtesy period on such urtext or critical editions published in the EU. In the USA, critical editions have not come before the courts, so they are theoretically protected just like an new original work is: 95 years from publication if published between 1923-1977 (with exceptions), or life of the last surviving editor plus 70 years if published 1978 and later. However, with important decisions about the "threshold of originality" like the above-mentioned case
Feist v. Rural, many very knowledgeable legal experts have stated that critical editions would most likely fail to meet the "threshold of originality" doctrine established in copyright case law.