@pk , Thank you for your reply. There is just a few things I want to clarify.
1) You said:
"By staying say 20 days in 2026, you are under the 'at least 31 days in the current year' -- for 2026 filing. All you are trying to do is not have to have dual status and its filing requirements."
Just to clarify, in this case I would not have dual status. Correct? Sorry, I just want to be 100% sure about these things.
2) About the "sourcing", you said:
"IRS generally follows the principle of 'sourcing' of income is where the work is actually performed. So if you do remote work , then the income is usually sourced to the country where the actual work was performed."
But the university will generate the W2 form informing the total amount they paid me during the three months, even if I go and work remotely February and March. Right? So, how would I inform that part of this income is sourced to Brazil?
3) About the last thing you said:
"Also because of NRA status ( your spouse is on a dependent visa ), you each have to file a separate return attached to the original MFJ 1040."
The original MFJ 1040 you mentioned is the one we will be filing in 2026 (for the calendar year of 2025)? I am asking because for the calendar year of 2026, either having dual status or only non-resident status, I have read that it is not possible to file as MFJ and thus I will have to file as married filing separately and my wife would file the 8843 form, since she does not have any income. So, you are saying she would need to attache our 1040 referent to the calendar year of 2025? I could not understand this part of your explanation very well, sorry.
Nice to know you lived in Brazil. I hope you enjoyed your stay there!
Best regards,
Felipe
