There was nothing salvific about believing in 1874, nor is there anything salvific about believing in 1914.
Your first question was to show you verses from the Bible and I did. What is significant are the events integrated with the dates. Those event, for example the birth of God’s Messianic kingdom in 1914 is important for salvation. It is also important for a Christian to submit to the authority of the Christ and his brothers. As JW interpret the Bible, Jesus appointed a faithful and discreet slave who dispenses food at the proper time, so Christians would need to work along with that. So having authority from Christ, they can explain the Bible. In the JW religion, Christ is king and leader and in a theocratic orderly way, as delegated authority progressively understands the Bible it dispenses it to be learned and accepted by other JW Christians. JW are students of the Bible including Brother Charles Taze Russel, so as students they are constantly learning and of course newer understanding replaces old. Take for example the new version of the NWT and 1975 replacing 1874 and other changes and enlightenment in Bible understanding. Obviously Christian conduct is what describes a Christian and that includes submitting to theocratic order relating to progressive learning of interpretation of prophecy and not pushing ahead.