I don't think Air has to be factored into this calculus yet. If I'm his dad, I'm saying, hold what you've got for now, soak it all in, and help them develop you and we can recalculate later. The portal, if necessary, is his friend when/if that time comes IF he's gotten as much out of his time at tOSU as he can. That last point goes for Sayin, or really any other QB, as well, but it looks like Sayin has pushed the issue forward.
So, that gives you four, but there will still be two at the front going into the summer. I think Howard wins out, for various reasons, but whether he does or not, he's gone after this year. That means Lincoln and Sayin are competing against each other to push Brown. If Brown loses out to Howard, he's out whether he stays or not. If he wins, he's still vulnerable to one of the next two and I don't see him being a multi-year starter in this scenario. I think Lincoln is a better version of Brown and Sayin may not be the same level of athlete, but certainly by next year he'll be a better QB.
If I'm Lincoln and/or Lincoln's dad, I'm looking at whether I can beat out Sayin next year, because he IS a multi-year QB. Once he's QB1, barring injury, it doesn't look like he's stepping down and Air is right behind him who's probably already a similar athlete to Lincoln and will only improve as a QB. Further, you've got to know that if you beat out Sayin next year, you've got to hope that he transfers or you'll have to beat him out again when he's got a year more development under him.
If I'm Brown, I'm leaving, the question is just when.