Well, here are the career stats between Dave Dickenson and Tommy Mellott (as of 12/15/2024):
Dave Dickenson (UM 1992-95): 1015/1477, 13,486 passing yards, 116 TD, 28 INT, 167.54 passer rating (Rushing stats: 388 carries, 479 NET rushing yards, 23 TD), 1995 1-AA (now FCS) national champion and 1995 Walter Payton Award winner
Tommy Mellott (Montana State 2021-present): 411/634 (64.8 comp%), 5676 passing yards, 52 TD, 8 INT, 164.57 passer rating (Rushing stats: 460 carries, 3266 NET rushing yards, 40 TD),
potential 2024 FCS national champion and
potential 2024 Walter Payton Award winner
Now let's not forget that Mellott still has one more game (potentially two more if they beat South Dakota), so it's possible that he could pass Dickenson in career passer rating. Now if the Bobcats had a more passer-friendly offense throughout Mellott's career, and if he had stayed healthy for all of 2022, then maybe his stats would be nearly equal to Dickenson's in terms of the passing game. But Mellott is the more productive of the two when it comes to calling their own number (and that's in part because of the Bobcats' offensive philosophy). Dickenson had 155 carries for 336 yards and 15 rushing TDs in 1993 (his first year as Griz starter) but he had fewer rushing yards than rushing attempts in the two subsequent seasons after that. Dickenson had a late-season injury at Boise State in '94 and then re-aggravated it in a playoff game vs. McNeese State, but he was healthy for all of the 1995 title-winning season.
If the cats win this weekend how many times will Tommy have led then to a National Title game? Do the Griz have any QB in their history that has led them to multiple National Championship games?
To answer your first question, this would be the second time Mellott will have led MSU to the FCS championship game (should they win over South Dakota).
As for your second question, no. When the Griz made consecutive title game appearances, they had a different starting QB each time: Dickenson (1995), Ah Yat (1996), Miller (2000), Edwards (2001), Bergquist (2008), Selle (2009).