I do not know where you live, but there should be a chapter of pilgrims association in your country - Like americanpilgrims.org. Since you have plenty of time, get one before you leave home. If you need to get one in Lisbon, I am almost certain toucan get one from the cathedral. That's where most people get their first stamp if they start from Lisbon.
As for the places to stay in Lisbon, or any other cities where albergues are not available, you can stay in a hostel about 12- 20 euros a night. Until you get to Porto, there are not that many albergues. That's especially true if you do not walk about 25 km a day. So plan to stay in hostels or even hotels. There will be far less choices of albergues compared to Camino France.
As for visiting Fatima, which is located in a hilly region, you can walk but you can also take a bus from Tomar or Coimbra.
If you decide to walk, there are blue arrow markers guiding you.
