I guess Tesin town would go to Poland as Benes proposed and what Czechoslovak generals were willing to sacrifice for good relations with Poland. I can see even further plebiscit in areas around Tesin where Poles and Czechs were mixed. There would be however very likely not changes at Kysuce, Orava and Spis region as this came only after Munich.
What I mean is, what if either side goes back on their word? 'Since Germany's backed down, we don't feel like having that plebiscite anymore' or 'we want Tesin back' or 'We just noticed a few more oppressed Polish minorities in your territory...'
Is that at all likely if Germany actually backs down? If a war does ensue between the Little Entente and Germany, the experience of shedding blood together might remove the incentive to renege, but without one...
As a side note, once Benes starts expelling the disloyal Germans, there will be a need for workers to replace them--could there be a wave of Slovak or Polish immigration to the Sudetenland? Poland had a chronic unemployment problem--jobs in Plzen could alleviate that, if something like a Schengen Area is implemented.
EDIT: I was also thinking a bit more about the plebiscite idea. I suppose the Czechs could agree to it, with some additional caveats (the right to use he railroad through Tesin/Cieszyn on a preferential basis), since the alternative is lacking allies at all, but the physical infrastructure in the area was just as much of interest as the people were. Specifically, the steel works south of the town itself were of great interest to both Poland and Czechoslovakia--an agreement might also need provisions for Czech assistance (financial or technical) in building more steel mills in Poland, if the mills themselves are not ceded. It won't be as simple as a plebiscite, and the full border adjustment treaty might take months to hammer out.
Still, in the short run, what's needed here is Poland to decide that neither Berlin nor Paris nor London can be trusted to preserve Poland, so she won't have a better shot in the future. If the Polish government realizes how dire the situation really is, they'd forego the steel mill until later.