I think we should assume from the outset that qualia are necessarily intensional, especially if we want them to play some epistemically foundational role, which is typically why they're invoked. If qualia have to be intensional, and the private language argument bars our associating any concepts with them then the private language argument contradicts the possibility of qualia. Not having concepts with which to talk or think about qualia means that we couldn't ever be aware of anything like a 'green' or 'painful' quale.

The private-language problem ought to tell us that even if raw experiences exist, then we should not expect to have words to describe raw experience.

Wittgenstein's private-language argument, if sound, would obviate 2c. But 3b is based on Wittgenstein's account not being successful in explaining the absence of private language. It claims to be a solution to the private-language problem, recognizing that Wittgenstein was unsuccessful in solving it.