US Expat...banking in Portugal (Cascais)

Hi. Relocating to Portugal with my family for Protected content from the US. Trying to figure out best options to handle banking. I will not be employed.

1). Do I even need to set up local banking, or can I just survive off of my US accounts?

2). If I do need local banking to survive....is anyone aware of intl banks that operate out of both US and Portugal? It would be far easier to start a relationship with a intl bank in the US, transfer some of my wealth, and then use this relationship to,transfer funds into Portugal, as needed.

3). Or...if not...what have people done in similar circumstances? Any recommendations?