Problems with Tag, Login button, Replys

Hi again, i have some problems;

1-) I want to change the style this button , its green (Photo1)
2-) Wenn i ask a question and write 2 times the same "TAG" its get error (Photo2&Photo3)
For Example; when i write two time "hello", "hello" on the "tag" textfield.
3-) I can more then 10 "TAG" write, how can i stop this at 10 #tag.
4-)When i wrote my first tag, tags automatically completing words,
but I do not want this word. I want my own words to tag.(Photo4)
5-)Why can i edit the another users reply ? I think its really big problem. I can also change your comment on Stackideas. users must change just own replys.(Photo5)
6-)When i ask a question, i cant edit my own question. How can i do it.
7-)How can i change the login fields ? i need just 3 field. Username, Email and Password. How can i custom this page ? (Photo6)
8-)When i click to login, i go to the page "http://www.mywebsite.com/index.php/component/users/profile";
How can i develop this Page?
I'll add all photos in the attachment