Merging the number is immaterial for the 2020 return ... you will file the 2020 return with the new SS# and you can get all the missing stimulus money you are eligible for on the 2020 return.
There are many changes to the tax laws in the appropriations bill that was just signed last week. There is no guarantee of when you will be able to file, it depends on when the IRS updates their forms and how long after that it takes Turbotax to be updated.
While Turbotax may allow e-filing as early as January 7, the IRS will not open e-filing until at least January 27, so early returns will just go into cold storage. Don't be in a hurry, especially this year.
The IRS has not yet finalized the Recovery Rebate Credit worksheet for the 2nd stimulus. TurboTax cannot include the 2nd stimulus question on the Recovery Rebate Credit page until the IRS finalized the Form 1040.
The IRS Form 1040 is currently estimated to be available on 01/07/2021 (subject to change)
Go to this TurboTax website for IRS forms availability - https://care-cdn.prodsupportsite.a.intuit.com/forms-availability/turbotax_fed_online_individual.html
