On the isolated_dwelling to locality change - everything points towards that nobody lives there. The place was already tagged as "ruins", Lantmäteriet map shows no data, and aerial images show no houses in vicinity. I looked there one more time and the place seems to lie on a forest trail with several other "ruins" isolated_dwelling placed around. Might also change them to place=locality tag.

On the usage of "S.", "L." etc. I am not a great expert on the topic yet, but everywhere I looked so far people use full names for places, or rather shorten the end of names, like "g." for "gata". However, "S:t" for "sankt"/"saint" - that gets shortened even on signs in writing, and I do not want to edit that, of course (maybe as alt_name).

>You caused a self-intersecting error as a result of a dragged node
Sorry!

For example, name on this place does not look right: node/6612629820#map=18/60.10883/14.16301 , but I do not know how to fix it.

Hello Andy,
No, but this is how places should be named.
Lantmäteriet Topographic Map which was used as imagery, shows correct full names on high zoom, and abbreviated names on low zoom levels. In cases when a "short" name is preferred, it is still kept as short_name tag. But generally nobody says for example, "S. Mörby", it is "stora mörby", "big mörby" if translated.