Non-dual intent visas
Non-dual intent means that you cannot file for an F1 once your AOS is pending. My lawyer has done many visa's for TN visa holders which is also a non-dual intent visa. Once you file for the AOS, you also need to file for a EAD and Advance parole, as the Non-dual intent visa is no longer renewable.
That's why it works with B-2 also which is a Non-immigrant intent visa.
You don't need an H1-b to file for AOS, but the advantage is that a H1-b holder can renew thier h1-b while AOS is pending, or if the AOS is denied. If AOS is denied, a person who applied for AOS while on a Non-dual intent visa is immiediately out of status.
I am not a lawyer, I personally know over 10 people who were on Non-dual intent visas and appied for I-485 which were all was eventually approved. Most were TN visas though.