One of my favourite topics to research is that of baptism. I have written an entire book defending the doctrine of baptismal regeneration from the Bible:
"Born of Water and of the Spirit": The Biblical Evidence for Baptismal Regeneration (2021 [for those who want a free PDF, drop me an email at ScripturalMormonismATgmailDOTcom])
While pursuing the minutes of some of the Schools of the Prophets in Utah/Idaho, I came across the following interesting excerpts dealing with baptism for the dead and the dead person's free-will ability to accept/reject the gospel (and the proxy work) being retained in the spirit world and an early discussion of baptism and its relationship to faith and repentance:
Minutes from the Paris, Idaho School of the Prophets, December 4, 1869
Prest. Rich said that everyone would receive the salvation they deserved. He thought that celestial glory would be reserved for those who obey the gospel in this life and prove faithful. He further stated that the ordinance of baptism for the dead did not interfere with the agency of man the dead. It would still remain with them in order to render the ordinance of avail in their behalf to acknowledge and receive the same. Prest. Rich also explained the order for baptism for the dead the oldest son for his father's family if his father did not attend to it. If the oldest son did not attend to it the second son should & so on. (source [Prest. Rich = Charles C. Rich, who was sustained unanimously as president of the School of the Prophets June 19, 1869])
Minutes from the Payson City School of the
Prophets, July 1, 1871
Elder Paul Gourley took the stand and preached an excellent discourse on the first principles of the gospel. Asserted that baptism in and of itself is not for the remission of sins. It requires Faith, Repentance and Baptism for the remission of sins. Elder Philip Sykes felt to coincide with the remarks of br. Gourley. Quoted the formula used in baptism as given in the Book of Doctrine & Covenants. Made some good remarks on the first principles. Elder J. W. Huish believed that baptism is for the remission of sins. Elder Hicks was of the same opinion. Elder H. Box made some remarks. Elder B. F. Stewart made some good remarks on the subject that had been introduced. We should never undertake to officiate in the priesthood or give counsel unless we have the Holy Spirit. (source; such fits with baptism, not being the meritorious cause, but the instrumental cause of initial justification and remission of sins, it having no energy/power in of itself to save, it being dependent wholly upon the meritorious cause [i.e., Christ's redemptive sacrifice]. See pp. 6-12 of Born of Water and of the Spirit for a discussion of different “causes” [meritorious; instrumental; final; efficient; formal])