I don't think the waiver provision has changed, which is still a big issue. I think that makes it very unlikely that Eason goes to the PS this year; it makes little sense to spend a 4th on a guy and then expose him to waivers, unless you don't think he's working out. If Eason looks at least decent in camp, I doubt they waive him.
If I had to project right now, it would be Kelly that gets waived, with the intention of signing him back to the PS. (Followed by more unreasonable but totally predictable outcry from the three Chad Kelly stans on this board.)
Part of this goes back to the hard-coded resistance some have to carrying more than two QBs on the active roster. That's great if you have an entrenched starter who never misses games, in his prime. But over half the league typically carries 3 QBs. If you have a shaky starter, an injury-questionable starter, an old starter, or any questions at QB2, it's logical to have 3 QBs on the active roster.
In the Colts case, we have an old starter, on a new team, and our backup shouldn't be considered a potential franchise level starter. So having a developmental guy on the active roster is not only defensible, it's preferable.
Btw, I hate that first year players have to go through waivers to be put on the PS. If that rule were changed, I think some of these young players that bounce around for three years and then wind up out of the league might have a better chance at sticking somewhere.