I left from Oviedo last year on Sept 26, arrived Oct 7 in Santiago. Many of municipal albergues were closed, and that meant staying the night in Campelliana after Tineo, and not making it on to Borres because they were completely full at the private albergue. Borres has only one food option (unless you pack food to cook from Campelliana or Tineo) regardless of time of year, so that won't change. Missing Borres meant that we went the "low route" and that was fine.
Smaller villages had some slim pickings for sleep possibilities, but until Melide we did not book ahead (a mistake only with Borres).
This year is busier so more things could remain open, but you are also going at a stage somewhat wetter and colder than when I went.
You asked "is it doable?" and I think it is... even if there is not always an abundance of choice.
I noted this year when I went back, that there were a few more private spots that had opened between Lugo and Melide. After Melide things got very busy so we slowed down *a lot* and slept at A Salceda, and at Lavacolla to get "off piste" but you might avoid those population crush problems by going a bit later.
Spouse was on the Ingles last year in *November* (first week), and found it perfectly fine, very navigable... so that might be a useful comparator.