score:7
I know that persons who have officially abandoned their LPR status (using Form I-407) can participate in the Visa Waiver Program. They should however take a copy of the processed Form I-407 with them so they can show airline staff that they have legally abandoned their LPR status. I assume that they can also apply for all types of visas, but I don't believe there is a way to adjust their LPR status into a visa category.
Granting a visa is however always at the discretion of the embassy staff, and entry into the US with a visa is always at the discretion of the CBP officer. Nothing can guarantee a visa and no visa guarantees entry into the US.