Nope.
Literally all my toons would be included except the very few brand new toons that I probably have favourited anyway. I currently have enough signal data and mats for a relic9 upgrade, which means I have enough for any relic upgrade lower than that.
I have a few g12 toons. All of them have a gear upgrade available because the only g12 toons I have left are older toons (a couple of Jawas, a couple Geos, a couple of Ewok's, CUP, Snow, Ughnaut, and ... something else. Oh, the Rogue1 useless pilot guy. With that heady, valuable stock available, I generally make sure that I have 3 of everything before I give any toon 1 g12 gear piece. That way as soon as I 7* one of the new, worthwhile toons, I can relic the unit instantly.
As soon as a marquee drops, I take them to g11 (even at 3 stars) so that they're available in GCs and Conquest. They have no ability to take more gear, since the g11 finishers are locked until 7 stars. BUT because they're only g11, I'm not going to drop an Omicron on them, and usually I even skip a zeta or two. So they have upgrades available as well.
Of course you can spend all your gear and mats as soon as you have them, but then they're not available for your best toons.
The system for this isn't sorting by "upgrade available." The system for this is "favourites". Choose only a few toons that you most want to upgrade right now. They stay on the top of. your roster and that way you can always easily see when a toon that should get the first upgrades is eligible for those upgrades.
This is a resource management game, and you won't get very far by throwing gear on any old toon unless you have enough to throw on every toon, and that doesn't sound like where you're at in the game.