I walked from León to Santiago leaving on 20 December and arriving on 30 December. You may find the following helpful.
León - The monastario Sta Clara will be open. If there is a problem go to the Hospedaria one door to the left and they'll re-direct you with map to the municipal albergue.
Virgen del Camino - I didn't stay the night, but the bar/albergue Tio Pepe near the church was open.
Hospital de Orbiga - You will arrive in February and it is the turn of the German albergue perroquial just after the church to be open. They run a rota - The private San Miguel open in November, the municipal in Dec & Jan, and the German one in Feb.
Astorga - Didn't stop but was told by people who stopped there one was open. Can't help with which one!
Sta Catalina - Both bars were open, and I think they have rooms, but I continued on to...
Rabanal - The refuge Pilar (on the main tarmac road, not the cobbled (?) road through the village. Nice and warm!! Eat at the meson by the church.
Foncebadon - The private one on the right was open, but we just stopped for Cola Cao!
Manjarin - open of course!
El Acebo - The bar/albergue on the left where we stopped for a bocadillo at on the left was closing from the next day (23 December) until late January
Molinaseca - When I arrived and rang (about 6pm) I was told it was shut, no water! Talking later to people, it may well have been he didn't want to come out to open it up at that time as it should have been open. Apparently, he also owns the private refuge in Molinaseca (also shut). So I walked on, by the main road, to...
Ponferrada - open, warm
Villafrance - Ave Fenix. Open, but with the showers being semi-outside and having a slate floor, it was COOOOLD!
Pereje - I didn't stay there but met people who had. No heating, key from bar.
La Faba - Open, only stopped for a tea. Nice fire inside!!
O Cebreiro - Open (Christmas Eve) Wonderful time, communal meal between about 15 pilgrims. Warm
Fonfria - closed until March
Calvor - I went via Samos, but I spoke to pilgrims who stayed here.
Samos - Open, but no heating
Ferreiros - Open, heating & dryer - but you must not use them at the same time ! Your choice !!
Portomarin - Open, but I didn't stay there.
Gonzar - open - I was having a break outside, and someone even came and asked if I wanted to stop there. I was carrying on.
Eirexe - closed for renovations
Palas de Rei - Both municipal open - the new one on the right before the town, and for me, the much nicer and atmospheric one in the town centre. Interesting showers!! (You'll see)
Melide - I didn't stop there but others did. They all said it was filthy.
Ribadiso - open, warm, kitchen, restaurant & bar closed, outside showers, but I continued to...
Arzua - Very atmospheric again, nicely equipped
Arca/Pedrouzo - open, but didn't stop there
Lavacolla - I stayed in the hostal San Paio, EUR25, nice. No albergue in Lavacolla
Santiago - Small hostel again. Sorry, Can't remember name. Other pilgrims directed me.
Drying clothes - Even in full sun, they don't dry on the back of your rucksack. If you can get one of those twisted clothes lines with a hook on either end, you can position your clothes over any heaters in the albergues. As there will not be too many people until after Sarria (!), you can generally arrange things as you wish.
I found the cold gave me problems only on getting out of the shower, with cold tile/shale or whatever floor at this time of year. I learnt to dry myself fully in the shower, and put my evening shoes on before exiting. I put socks on when sitting on the bed to keep my feet off the cold floor. It was surprising how long it took for my feet to heat up again until I sussed things. (shoes may be a mis-description, I found some cheap Croc-type shoes, only 250grams, GBP5/EUR7, nearly 400g lighter than the sandals I take in summer)
Don't get worried in advance. Make sure you have the right clothing, take any advice of locals regarding weather, and enjoy yourself. You'll see everything will fall into place and you'll have a wonderful time
Mike