Seeking D7 for 🇵🇹 for family

I’m trying to figure out if I should go ahead and get an immigration lawyer to handle my Portugal visa paperwork not only due to expedience but because I have had a horrific experience with VFS in the US.

I am in the process of buying a house in Portugal and am told by my bank that I would have better loan terms if I already had my visa. But my understanding is that I cannot apply for the visa until I have an address in Portugal? I don’t want to throw away money on a lease for an apartment I will likely never use but it is a substantial amount of money that I would save over the life of my mortgage loan (roughly a few hundred euros each month).

Does anyone know if I can qualify for the D7 visa prior to arriving in PT? I don’t want my visa to be sent to the house in PT since it will take time to close…any advice is greatly appreciated.

Also any tips for family members accompanying me for the visa process, do they each need to have visas issued as well? Eg my children? I have an adult son in college who is considering joining us later once he’s finished school in a year or two…