How would we determine which skaters fall into a gray area and should get GPF spots?
Perhaps those who placed/will place high (first to second/third) at their other event, so realistically would have had a chance to qualify for the Final if they placed highly at TEB as well? That could add people like Aaron, Chan (if he doesn't qualify with the fifth place standing from the SP), probably also Murakami (since two third places would have most likely been insufficient, but he could have placed higher overall if he had skated also the FS) in men, Tuktamysheva in ladies, Tarasova/Morozov and Peng/Zhang (if they place high at their next event) in pairs, as well as Gilles/Poirier and perhaps Stepanova/Bukin (if they win over Hubbell/Donohue and take second place at NHK).
But I think it can't be mandatory that only an exact number of skaters/teams (two, for instance) should be added to each discipline in such case.
Because, what would happen then?
If Chan qualified anyway based on his SC win and the fifth place in the TEB SP, and Kovtun qualified based on the TEB SP placing and his placing at the next event, and also Hanyu, Fernandez, Boyang Jin and Uno (based on his SA result and TEB SP placing) qualified, Aaron and Murakami could be added. In the scenario where Brown qualifies by winning silver at NHK and Kovtun places fourth it could be Hanyu, Fernandez, B.J., Uno, Brown + Kovtun, Chan and still Murakami (as two third places should give priority over Aaron's first and seventh in the TEB SP). That would still leave Aaron out.
From ladies Gold and Tuktamysheva really had a chance for the GPF from the ladies skating at TEB. Murakami would have had a slight chance by winning the event, but she was fourth also at the TEB SP. Gold qualifies for the Final already with the SP placing, so only Tuktamysheva can be added from those who didn't place that well in the TEB SP which would mean that six ladies should qualify from the other events. Those would most likely be Asada, Wagner, Medvedeva and three of Hongo, Radionova, Miahara and Pogorilaya. But what if Radionova places first to third at CoR, Hongo places first to fourth, Pogorilaya places first to second at NHK and Miahara places second to third there? That would be four ladies who would deserve a place at GPF more than Tuktamysheva with her second and fifth place (according to the usual rules). Again, this would leave Tuktamysheva out, otherwise it would be unfair.
In pairs, Yu/Jin with two third places or even a third and fourth would deserve a spot more than Tarasova/Morozov with their second and seventh. So would Scimeca/Knierim with second and fifth/sixth, James/Cipress with the same, Seguin/Bilodeau with what they already have, Stolbova/Klimov with fourth and even third, and so on. I don't have time to write about ice dancers anymore, but I think the gist is clear.
Sorry, I didn't get to read all the comments before mine, so I don't know what other posters have suggested. Perhaps much more precise solutions have been offered.