In my opinion, you have put your finger on an important problem - namely, the identification / detection of simple oxygen-containing organic species. The whole question of 'oxidation' chemistry seems to be poorly understood. I am especially interested in the conclusion that the identification of propynal may not be secure! A friend of mine investigated the reaction of HCCCH (ground state triplet) with O2 (ground state triplet). The reaction happens in a matrix at 10 K. Propynal is only one of the products. There are other species that contain BOTH of the oxygen atoms: two are exotic structures (a carbonyl oxide and a dioxirane), and two are not (propargylic acid = propynoic acid = HCC-CO2H; and ethynyl formate = HCC-O-CHO). Take a look at the attached structures. The reactions of O2 with c-C3H2 have not been studied, but we should be able to so it, straightforwardly. Sounds as though you think this might be worthwhile.
While we're at it, I should mention that propadienone, H2C=C=C=O is a kind of odd species, chemically, as the heavy atom backbone is NOT linear.