Walked this route three times (last time in 2021) and am sad to report that there were no places to stay on either of those segments. Additionally, there was no place to stay in Izco, so you have to walk all the way from Sanguesa to Monreal is you follow the main route! Additionally, we found zero places for food and water over this segment; thankfully we carried our own supply. You may have better luck depending upon the time of year that you walk, but April/May found the water taps non-functional.
One alternative is to take the variant through the Foz de Lumbier and stay at a hotel in the village of Lumbier, but that still entails a lengthy walk from there to Monreal the next day.
The Aragon route is lively, but it definitely has some gaps in services.