We have made a Webcast in collaboration with the Aritmosoma (https://www.aritmosoma.pt) accountancy company answering the most common doubts about the Portuguese fiscal system for Ukrainians!! Watch it here → https://www.youtube.com/watch?v=zk03M-6jBWk
Also, you can find a general FAQ for Ukrainians in this link. It’s only in Portuguese (go figure) but you can use AutoTranslate: https://portugalforukraine.gov.pt/faqs-pt/
Legalisation issues such as lack of documents and children, you can find free support at: https://www.ucrania.notarios.pt/ua/