In Atahualpa I can set at "Configure EXERPTS"-> "Post or Exerpts on CATEGORY (ARCHIVE etc.) pages" two mode for all posts: "Only Exerpts"/"Full Posts".

But how can I select this mode for certain post (by ID, for exemple) not for all?

If you could set a post to only ever show an excerpt, how would you read the rest of the post?

There is no easy way (unless you can find a plugin) that I can think of. You could dig into the code and put a condition in so that if post_id_xx and you were on a multi post page, do the excerpt instead of the full post.

You would have to document this so when you change releases you could make the change all over...

You would want to look at the code in bfa_post_parts.php around line 107 (version 3.4.4)

Thank you so much.

I have tried to find suitable plugin, but unsucsessfully.

Now I have only a halfway result: clcking to top category doesn't show posts from children categories( plugin "Just One Category"), but only single post's title which linked with this category.

Another way is "Category Page" plugin. It links category to page.
But it doesn't work correctly (or may be I am not enough skilled).

And last foolish question...

In principle is it possible to put some code above loop similar: " if post id=xxx then call page id=yyy"?

You might want to take a look at the List Category Posts plugin as well.