We have to ask ourselves some questions first:
1) Can P2Pol be oxidized to P2P with sodium hypochlorite? Yes it can, for example with a PTC:
https://www.thevespiary.org/rhodium/Rhodium/chemistry/ptc.naocl.oxidation.html
By necessity, the sodium hypochlorite needs to be in aqueous solution for the oxidation, but P2Pol is not water soluble, I don't know what the result would be without a PTC. But a two-phase PTC reaction is all right here, the organic phase is already present (if ether was used for the grignard, THF is water miscible and would have to be evaporated and replaced with another solvent) and the hypochlorite solution provides the aqueous phase.
2) How vigorous reaction conditions are needed to decompose the magnesium alcoholate? In some instances, mere addition of water is enough, in other cases long acid reflux is needed. I don't know about this case. If it is easily decomposed to the alcohol, then water may suffice, or perhaps just one molar equivalent of acid would be needed, and the proposed reaction is indeed feasible.
3) Can hypochlorite really oxidize alcoholate salts to ketones? Probably yes, but the formation of increasing amounts of NaOH will inhibit the reaction speed (negligible, or too much? I don't know, testing is in order.
Aqueous sodium hypochlorite (NaOCl), or common household bleach, can be used to oxidize secondary alcohols to ketones. The reaction occurs more rapidly under acidic conditions, so it is thought (we're not actually sure) that the actual oxidizing agent is hypochlorous acid (HOCl), generated by the acid base reaction between sodium hypochlorite and acetic acid. In alcohol oxidations, the reaction probably proceeds via E2 elimination of the alkyl hypochlorite produced by reaction of the initial alcohol with HOCl.Taken from
http://www.chemistry.mcmaster.ca/~chem2o6/labmanual/expt7/2o6exp7.html
4) Will any of the species in the grignard reaction mixture interfere with the oxidation? Hard to say, but the bromide/iodide from the grignard reagent will likely be oxidized to the free halogen by hypochlorite - and this halogen may again react with the P2P, forming an alpha-halo ketone.
It sounds like it is worth a try, definitely. Who will be the first to perform this reaction?
And finally - No, I haven't seen any discussions about this one-pot P2P synthesis earlier, and there are only 20-something hits in the database on "propylene oxide grignard", and noone of the posters there seems to have performed it, they just mention it as an alternative pathway.