Hello
1. If you in Miranda NG I will read the message, this chat on page Facebook also selects as read?
Yes. In Miranda's options you can also disable marking messages as read on server. That way Miranda won't set them as read so they will be marked as read automatically only after you send message to that contact.
In default options Miranda will mark them as read immediatelly when message is received to Miranda (IF you have already opened the message window of contact). If you don't have opened message window (and new message is "blinking" in systray, then message will be marked as read after you open the message window.
2. If you friend send to me sticker, this Miranda NG display in your chat window? Or no and only give link?
Miranda will give you URL link. There is partial support of showing it when you have in SmileyAdd and in Facebook options enabled "Custom smileys support". But it doesn't work so well and often causes small freezes (<1 sec.) when receiving message with sticker.
3. Or status invisible working in 100% properly?
Yes. Invisible status means you have "disabled chat" on website. But you can still see statuses of other people and you can communicate with them.
4. And generally, or all features written here working properly?
Yes, all features should work. If something doesn't it's probably due to some change on Facebook server and should be reported (to Miranda's issue tracker or at least forum or me directly) and it will be fixed.
5. Can I send images and/or files in chat window to friends?
No. There is no support for sending images/files to other contacts or to posting them as status to wall. This might be implemented in future.
And "Notification after someone remove you from his friends" works at login when it compares previous friends list with actual friends list. Which means it's not instant and it compares only changes.