Correct on both. Now, which ones?
On the Tveitt it must be the Sonata No. 2, since apparently that's the only one that survived, unless you are
wayyyyyyyyy better at finding sheet music than I think (and I think you're pretty good).
Medtner... I dunno. His are in Em and Cm, and that section is Ebm, and Ebm/GbM don't really have anything to do with Em/Cm. So, I have no idea. From that little bit of information, I'd just assume it's not the Em one and one of the Cm ones (vaguely makes more sense harmonically). But, unfortunately, that still leaves two x: From that I'd guess No. 1, because I remember that being a better piece than No. 2 (imo), and why would you upload an inferior piece?
So, it's probably No. 3 and I am just being a retard again D: But no, I'll guess No. 1