Fiqh
What is the definition of a sahabi? Is Najashi (The Abyssinian King) a sahabi?
A person who has seen the Prophet (PBUH) and believed in him, and died as a muslim. No because he didn't see the Prophet in his lifetime.
A sunnah salah that you can pray only 1 rakah
salatul witr, you can pray as 1, 3, or 5