Parents stay extension - B2 visitor visa expiring

[GautamSen]

Hi Everyone,

My parents visited us in March and lockdown started after their arrival. They have their I94 validity till 4th September and B2 visa is also expiring on 10th September'2020.
There is no regular flights this time and to avoid quarantine process and covid-19 risks, I applied for their current stay extension requests for few months by filing I-539 for each of them (mom n dad) online which are in PENDING status at present.

I have few questions.

1. Is I-539 filing is good for both I-94 and B2 visa extension ?
2. Can they get a I94 extension for another few months even if their B2 visas are expiring ?
3. I understand there is a separate process DS-140 for visa extensions. But, all non-immigrant service contact line have been suspended till-date and department of states offices are closed for non-immigrant cases. Hence, I am not sure if I should also file for DS-140 extensions?
4. What are the options i have for their stay extension by few months if both I94 and B2-Visa expiring same time in September 1st week.

I would appreciate any help or guidance here.
Thank you all in advance.

[newacct]

US visas are only for entry to the US. There is no "visa extension"; you can only apply for a new visa at a US consulate outside the US. You can't apply for a visa inside the US because, if you are already in the US, you do not need to enter.

The visa expiration date has nothing to do with how long they can stay in the US. They can be admitted for longer than the visa expiration, and they can get extensions of stay longer than the visa expiration.

They would just file I-539s for Extensions of Stay (it extends their B2 status; if approved they get a new I-94). It has nothing to do with the visa.