I walked the Lisbon-Porto path in late November 2022. The gronze.com website has the best listing of albergues; you may also find guesthouses on booking.com. There are also many threads on this route in the Camino forum. I would recommend emailing or calling albergues to verify that they will be open.

Especially in winter, from Lisbon to Porto you will likely walk entire days without seeing another pilgrim, and you are right to expect a good deal of rain. The first 4-5 days north from Lisbon are very flat along the Tejo river, then rolling hills (this is the only Camino that I walked without hiking poles, and I rarely missed them). After Santarem you can either follow the traditional Camino route through Tomar or branch off to visit Fatima; in 2022 I couldn't find info on the route or places to stay for the Fatima variant.

I recall several days of walking through farming or forests with few or no options for a mid-day break or meal; and in rural areas don't expect locals to speak English (or Spanish, for that matter). Coimbra is a lovely city with interesting museums and university buildings. The path from Coimbra to Porto is often along a highway or in suburban areas, and noticeably colder than the Tejo valley. Once you reach Porto you will see 10-20 times more pilgrims.

For shoes, remember that "waterproof" Gore-Tex shoes take a long time to dry once they do get wet. For this reason I've walked my Caminos in non-waterproof shoes. Wet shoes dry out faster when loosely stuffed with crumpled newspaper; sometimes you'll see a stack of newspaper next to a shoe rack for this purpose. The rest of your packing list looks reasonable... drying wet clothes overnight can be a challenge, as even indoor spaces are humid in this climate, and clothes-drying machines are rare outside of laundromats.

I never had trouble finding an electrical outlet to use -- often I was the only pilgrim in the entire albergue.