I like all your questions. Mormons probably believe that John the Baptist had the Priesthood.
Upon you my fellow servants, in the name of Messiah, I confer the Priesthood of Aaron, which holds the keys of the ministering of angels, and of the gospel of repentance, and of baptism by immersion for the remission of sins; and this shall never be taken again from the earth until the sons of Levi do offer again an offering unto the Lord in righteousness.
He said this Aaronic Priesthood had not the power of laying on hands for the gift of the Holy Ghost, but that this should be conferred on us hereafter; and he commanded us to go and be baptized, and gave us directions that I should baptize Oliver Cowdery, and that afterwards he should baptize me.
Accordingly we went and were baptized.
The messenger who visited us on this occasion and conferred this Priesthood upon us, said that his name was John, the same that is called John the Baptist in the New Testament, and that he acted under the direction of Peter, James and John, who held the keys of the Priesthood of Melchizedek, which Priesthood, he said, would in due time be conferred on us, and that I should be called the first Elder of the Church, and he (Oliver Cowdery) the second.
Immediately on our coming up out of the water after we had been baptized, we experienced great and glorious blessings from our Heavenly Father. No sooner had I baptized Oliver Cowdery, than the Holy Ghost fell upon him, and he stood up and prophesied many things which should shortly come to pass. And again, so soon as I had been baptized by him, I also had the spirit of prophecy, when, standing up, I prophesied concerning the rise of this Church, and many other things connected with the Church, and this generation of the children of men. We were filled with the Holy Ghost, and rejoiced in the God of our salvation."
[5]
Aaronic priesthood (Latter Day Saints) - Wikipedia
Young Priesthood Holders:
However, the lack of adult men willing to serve in Aaronic priesthood was ultimately the determining factor in the LDS Church ordaining youth. Young instructed Hunter in 1873 that each stake should have a full quorum of priests, teachers, and deacons; however, Hunter complained that he could not find willing men to fill these positions.
[20] One bishop noted, "It is a difficult task to find a sufficient quantity of efficient teachers. I have thought of calling upon some of the boys."
[20] Another stated, "It is very hard to get the older men to act as Teachers, but the young men come forward and are willing to take their parts and therefore we have to appoint young men where older ones should be." By the time of Young's death, he had taken the position that all boys needed some priesthood experience and that they should receive the Aaronic priesthood before reaching adulthood.
[21]
Aaronic priesthood (Latter Day Saints) - Wikipedia
A person may be temporarily guided by the Holy Ghost without receiving the gift of the Holy Ghost (see
D&C 130:23).
However, this guidance will not be continuous unless the person is baptized and receives the laying on of hands for the gift of the Holy Ghost. We read in
Acts 10 that the Roman soldier Cornelius received inspiration from the Holy Ghost so that he knew the gospel of Jesus Christ was true. But Cornelius did not receive the gift of the Holy Ghost until after he was baptized. The Prophet Joseph Smith taught that if Cornelius had not received baptism and the gift of the Holy Ghost, the Holy Ghost would have left him (see
Teachings of Presidents of the Church: Joseph Smith, 97).
Today people who are not members of the Church learn by the power of the Holy Ghost that the Book of Mormon is true (see
Moroni 10:4–5). But that initial testimony leaves them if they do not receive the gift of the Holy Ghost. They do not receive the continuing assurance that can come to those who have the gift of the Holy Ghost.
Chapter 21: The Gift of the Holy Ghost
Who laid hands on Oliver Cowdery and Joseph Smith for the Gift of the Holy Ghost?