Right to return to the U.S. if I-94 was denied, but have valid B1/B2 visa

Yes. If you have a valid B1/B2 visa, you are permitted to use it to re-enter the US. It is possible, however, that the US Customs & Border Protection inspector at the airport might question your intent as the computer would likely show that you have spent a lot of time in the US recently. So you would have to analyze your documentation of intent and perhaps bring documentation of your temporary intent. This is an area of extreme discretion, so you would be want to be careful how you handled it.

But from a legal perspective, you should be valid for re-entry.

Whenever you want to come into the US as a visitor, you must be able to prove your bona fide nonimmigrant intent , showing at each entry that you have a lawful, finite purpose for your temporary visit that does not include working or attending school (both of which are prohibited under B1/B2 status). If you cannot prove these things to the satisfaction of a USCBP Inspections officer, they can deny you admission even if you have a valid B1/B2 visa.

Also, there is the question of whether you have the receipt from your past I-539 filing, to show that you did not overstay, but had a timely-filed application to extend your stay, and you should have the actual plane ticket stub & flight itinerary to prove when you left, since the US does not stamp your passport when you leave, and your home country does not stamp your passport when you enter.

If you are staying fin the US for 4 or 5 months at a time, you need to be able to explain the legitimate source of the funds on which you are supporting yourself, and the legitimate, finite, temporary reasons for these long stays. I highly recommend that you discuss the specifics of your situation with an attorney.

To add to great answers above, you should carry with you proof of non-immigrant intent, such as family, financial and work ties to a home country. I generally recommend you spend in the US less than half time, and describe to the CBP officer your plans while here.

Also, please check your passport to make sure they did not cross your visa. If yes, you have to go back to the consulate and get one reissued...