I'm not an Eli Manning fan, but there's nothing borderline about his HoF credentials. He's a lock to be inducted within the first few years of eligibility and many pundits think he'll be picked first ballot. As far as I know, they don't publish the HoF balloting but there's no such thing as unanimous selection (it's possible but unknowable). Basically you have to be one of 5 "Modern-Era" finalists each year, and also exceed 80% positive vote to get in.
I used to have Marino in my all-time list, but as time goes by, he gradually drops down the list. You have some weird anti- Aaron Rodgers fetish, so again, we'll have to agree to disagree. Superficially, Rodgers and Favre have similar credentials (3 MVPs, 1 Super Bowl win). But statistically, Rodgers is par excellence until the arrival of Patrick Mahomes. I'll concede you cannot compare stats across eras, and RPD is absolutely correct that what Marino did early in his career is insane compared to his contemporaries.
The main knock on Rodgers is he doesn't have the clutch gene of a Tom Brady or John Elway. He doesn't have as many comeback wins as some of the all-time greats, despite having some memorable hail mary plays. Having said that, Brett Favre was just the same. Meanwhile, Favre was an interception machine that by career's end had somewhat mastered the art of chucking the ball out there for DBs to pick off. I realize you're alluding to the eye test, but there's no universe where Favre is substantially better than Rodgers. If Favre is just in front of Rodgers, that's fine, if highly debatable. But not greatly superior as your Marino vs. Rodgers vs. Favre comparisons imply.
I realize I'm biased in this matter and I don't have any problem with Marino being a few spots ahead of ARod. All I said earlier is that it's interesting to see it. Rodgers career possibly has a few good years remaining to climb higher up the list.