I think stimulus check is part of 2020 tax credit. So I read some blogs saying that if your income reduces or have a new child in 2020, you will get the stimulus check when you file tax returns in 2021 according to that. I think If you are able to get SSN for your wife now and you may get the tax credit or stimulus check when you apply 2020 tax returns in 2021. I am not 100% sure on this. But you can try. May be tax experts can shed some light on this.
