Back to the part you ignored which shows the text of Mark 16 was addressed only to the Apostles, not every one else.
Mark 16
Even so, verses 14-15 lets us know the statement was addressed to the Apostles only, not everyone.
14 Afterward he appeared unto the eleven as they sat at meat, and upbraided them with their unbelief and hardness of heart, because they believed not them which had seen him after he was risen.
15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.
Paul is the only one I remember who was bite by a snake.
Matthew 28
16 Then the eleven disciples went away into Galilee, into a mountain where Jesus had appointed them.
17 And when they saw him, they worshipped him: but some doubted.
18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
Context Matters.