I have a question. May i register a .bit domain and renew it for like 10 or 20 years in advance at once?
Or do I have to renew it every 200 days or so? If it so, then it would be easy to loose your domain.
Unfortunately something like that is not (yet) possible. The closest to implementation is a grace period during which a domain seizes to work but still can be renewed. Also it would be relatively easy to create a program/service to warn about expiry.
I have a question. May i register a .bit domain and renew it for like 10 or 20 years in advance at once?
Or do I have to renew it every 200 days or so? If it so, then it would be easy to loose your domain.
Is Namecoin still in development ? Is there a future for .bit or is Namecoin Dead?
yes and there is a bright future ahead

someone could start another coin and issue .bit addys or do something similar correct?
Yes but it would not be the same.