"THEM" in Mark 16:17 refers to the ELEVEN as recorded in verse #14.
In the Greek grammar, the "ANTECEDENT" of the word THEM in verse #17 is actually the ELEVEN in verse #14.
Definition of antecedent
Definition of ANTECEDENT
grammar : a
substantive word, phrase, or clause whose denotation is referred to by a pronoun that typically follows the substantive (such as
John in "Mary saw John and called to him")broadly : a word or phrase replaced by a substitute
You are free to believe anything you want to believe. You are just as free to believe that you have cast out demons if you want to and that you speak in tongues and make sounds that no one understands.
All I can tell you is that the Bible can not be used to validate what you believe that you want to do.
The GREEK GRAMMER simply does not allow it to be the case.
YOU are NOT one of the ELEVEN as you posted from Mark 16.
YOU are not an Apostle and YOU and no one else has the Sign Gifts.
No need to argue that point with me, go and use any Greek concordance, Strong's, Vines or anything else and you will find that they confirm what I just said.