To answer both questions: Yes you can play them in 480P tate on a TTX2, you can play either the Nesica versions or TTX1 versions. The TTX1 versions when played on TTX2 have some graphical errors, particularly on Raden III. The Nesica versions from what I've heard don't look as sharp in 480P as the TTX1 versions, because of some scaling or filtering issue. I haven't tested this myself (no 31khz CRT cab... yet), but have heard this from others. So you have the choice of graphical errors or unsharp on TTX2.
The best thing to do is simply play them on the original hardware, a real TTX1.