a couple (seniors) applied for extension of stay in the US around 45 days prior to I-94 date. They got a denial after 30 days of overstay. They left US after a week of receiving the notice.
Now after 7 years they want to return back to US.
1) Is their multiple entry visa still valid?
2) What docs they need to show at port of entry?
3) If visa not valid - can they get a new one without a problem?
4) What docs they should take to the consulate to get a new visa?
If the multiple-entry B-1/B-2 is still unexpired, it is still valid and they need not apply at a consulate for a new one - this doesn't mean that they will have an easy time getting in after what will be perceived as a prior overstay.
On the other hand, it is good that this wasn't a "straight" overstay by ignoring the expiration date - they did timely file for extension, and when the extension was denied they promptly left. They should bring, if available, evidence of the extension filing (including the original I-94 to show it was filed timely), evidence of their departure shortly after the Denial date, and evidence of their intent to return home after only a short visit this time (jobs to return to if not retired, homes/other assets, other things that will ensure their return).
Seek an attorney's advice for further guidance.