Yes you can register a company as a sole director. You can have all the shares if you are not planning to add someone in future or leave some shares if you may want to add someone in future.

Yes you can register a business name if you are a beginner. After stabilizing, you will do what is called conversion and in that case, you will change your business name into a Private Limited Company with the name retained.

Yes, after registering a company, you will get KRA pin and you’ll be expected to file NILL Returns if you have not been operational. On the other hand, you’ll be expected to file Annual Returns with the Registrar of Companies every year.