Your proposal is written as overly-prescriptive, and risks sending people down these prescriptive paths rather than leaving things open for broad exploration. (This is a comment on writing style, not intention.) The crux of your proposal is a separate class of state with different behavior.
UTXOs indeed have a number of nice properties over accounts for certain applications. A novel proposal from more than half a decade ago that is very similar to your hybrid UTXOs idea was posted here: