So far as I can tell:
Pretty sure I'm right on TMBG; the physical copies of their albums are pressed and distributed by an RIAA affiliate but they have full ownership of digital versions.
MC Frontalot doesn't appear to have ever been affiliated with an RIAA label. Neither do Christopher Tin or Jonathan Coulton.
OK Go used to be with Capitol but formed its own label in 2010.
That leaves Valkyria Chronicles.
Wikipedia lists Sega as an RIAA affiliate but the
RIAA site doesn't; the Best Of compilation appears to have been put together specifically for this bundle, and I don't think there's been any other soundtrack release in the States, so I don't think the RIAA's involved on that one but I'm not 100%.
So I THINK everything is in fact good and indie. But it would sure be easier if the Bundle page included all that info!