So every translations has to be certified? Going to be expensive when every Portuguese receipts is going to cost me $25 per translation...
Yep. You can double-check the requirements, of course.
My suggestion would be to cut down the volume of docs you provide and focus on quality.
If your case is fairly straightforward, it may be that you can leave out some things.
Don't know your case but e.g. you're married so you can focus less on providing docs to meet the minimum time residing together test.
Depends on how long you've known each other, time spent physically together, etc.
But no mistake, if your application depends on the documentation, pay to have it translated acc to requirements. If in doubt, keep in mind that things not done correctly or insufficient documentation can lead to delays and problems later.