The idea behind not letting people log out instead of summoning is good in theory, but the reality is that it's a giant pain in the ass for ever being able to track people. It's also a nightmare if you ever have your internet crash while you're out and about. My suggestion would be to let characters log out as long as they have a hearthfire and for scents to be summonable at the hearthfire again. Summoning would instantly kill the character to avoid any shenanigans with summoning people back with redhanded/in combat situations. If you have no hearthfire you can't log out, if your hearthfire is broken with scents out, you're summoned and killed at the fires location.
The 2 man advantages to this system would be that you don't leave your character stuck out in the wilderness for long stretches of time if you disconnect with scents and also that it would be much, much easier to track people who leave their hearthfires again like in legacy because you could see when the player is actually online.
Alternatively, make it so you can see when the perp is offline (but still point to the perp for obvious reasons) when you track so it's easier to tell when a perp is active.