in-laws overstayed for a month

[r70]

My in-laws overstayed for about a month. This is because they were waiting for their visa extension which was refused (and the notification came after I-94 expired). They left voluntarily after a month.
Some questions:
1) Is their B1/B2 tourist visa still valid, and they use it to come back next year?
2) Also, would it be appropriate for them to come after ~ 8 months after they left the US, OR should they rather wait for a year to come back?
3) if their earlier visas are invalid, what chances do they have in getting a fresh tourist visa? They have strong family ties to India and have no desire to immigrate. Will their extension denial and overstay go against them?
many thanks for guidance.

[immihelp]

1. Invalid. Need to apply again.
2. Later is better.
3. Really depends.

[sbs2010]

Similar Situation/ Extend of Visitor Visa

Hi r70

I have similar situation, but waiting for response from USCIS to application. Can you please reply with little information?

How long ago did you apply for extension for your in-laws?
How many days before you applied from date on their I-94?
And if you track procedure timing, after how many days or months you received a denial from USCIS?

Your response will be greatly appreciated..! Thanks