then at least No for any flight before 10/25. Since CO will not be with *A before that date.

You could post the miles say to UA and then if you have the return flight after 10/24 post the return flight to CO, thats if all goes according to plan and CO is with *A on 10/25

But beware you might be on a fare basis that might get you UA credit but not CO credit, as of now we dont know what fares will yeld what mileage if any both for RDMs and EQMs. There probably will some fares that wont earn either RDMs or EQMs