Green card but no social number, how to get stimulus check?

My parents-in-law both have a green card (legal US permanent residents) since the beginning of 2020. One of them has a social security number and the other didn't have it issued. The SS office is close due to COVID and currently unable to get her SS number. Their income is lower than the required threshold to file taxes, but they would file anyway if they can get the stimulus checks. Questions:

1- Is she allowed to file for ITIN in this case?

2- Will they be able to get either stimulus check #1 or #2 using ITIN, given that the other spouse has a SS number? Or at least the spouse with SS number, can he get his own stimulus check(s)?

3- If they can't get the stimulus unless they have both SS numbers, how can they extend the filing due date beyond April 15 till perhaps the SS office is reopen?

4- Is there a place in TurboTax where one can tell that this number is not an SS number, rather it is an ITIN, so that the stimulus checks get decided and calculated correctly (if eligible for say the second only)?

 

I appreciate any response. Thank you.