Yes, the Fénix is still a good choice although you could also try Avenida Palace http://www.hotel-avenida-palace.pt/ or York House (not so well located). http://www.yorkhouselisboa.com/

Your itinerary is ok. I like Aveiro very much. Maybe you should also see Óbidos, some 80 km north of Lisbon, ang Guimaraes (North of Porto) on the way to Viana do Castelo.

The suckling pig is a Mealhada speciality and I like "Meta dos Leitões" or "Pedro dos Leitões" which are two Mealhada restaurants serving it.

I believe that Douro trip will be ok because the weather will be fine (not so hot as in September).

Of course, we could also get a GTG and have dinner on a good restaurant in Lisbon.

Best regards, João in Lisbon, Portugal