As
@topher694 says, there's little point in replying to you, because you have no interest in any other opinion, nor do you engage with the evidence.
The context of the last part of Mark16 is the unbelief of the disciples when faced with the evidence.
14Later He appeared to the eleven as they sat at the table; and He rebuked their unbelief and hardness of heart, because they did not believe those who had seen Him after He had risen.
So my friend, where would you be on the scale of unbelief, given you reject the scriptures and reject the evidence of those who walk today in those same commands?
But, for the gospel's sake, I shall attempt to answer your points.
1. Context = preaching the gospel
2. Spoken to the disciples
3. Although still limited by their unbelief, the disciples would understand the words just as Jesus commanded them, go into the world and preach the gospel to all mankind and watch for the signs that would follow those they preached to.
So yes, the command was given to the disciples, but it concerned the whole world.
Also, Mark16 has to be taken in conjunction with what Jesus said in the other gospels, notably
Matt28v18And Jesus came and spoke to them, saying, “All authority has been given to Me in heaven and on earth. 19Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20teaching them to observe all things that I have commanded you; and lo, I am with you always, even to the end of the age.” Amen.
As can be seen here, the disciples were commanded to make further disciples of all nations, and being disciples, the same command would guide them, ie, evidence of casting out demons and speaking in tongues.
Exactly as we still see today among those who believe!