@steevbe you are welcome . Great that you had done your research. Clearly you are looking for a different answer -- however I would like to point out that based on your questions
1. should you make the first year choice -- ONLY you can answer that -- the differences are substantial as pointed out above , lower tax rate, deductions, credits etc. Basically, unless you had Non-US sourced income during the period of your stay here during 2019, it is always better taxwise to files as a resident
2. once you choose the resident for tax purposes status, you are not dual status anymore -- unless you make the first year choice you would be a Non-Resident Alien for the year 2019 and thus file your return on form 1040-NR or 1040-NR/EZ
3. As you can see form the citations once you are a resident with SSN you may be eligible for the Economic Impact Payment.
Good Luck
