I walked the coastal senda in June this year arriving in Viana on independence day. The town was much decorated and there was a concert in the square which I watched from my room. In the evening there seemed to be a special civic event in a hall near the harbour...in general the festivities were pleasantly understated and shops, restaurants etc all open as normal.
I have family in Portugal and unfortunately the fires are always a big deal there. I wasn’t sure if the independence celebration would make it tough to find a place to stay or crowd a certain area while I was hiking the Caminho. Thank you for the response.