Question about buying a home during the redemption period

[J.R. King]

I have a house about to go under contact right now.  It was forclosed on by the bank, and is now in the redemption period, until the end of April.  The owner is willing to sell the house to us, but wants to stay in the house until April, so that they aren't moving in the winter.  What do you think the best way to handle this offer would be?  Pay the bank now directly, and give the seller free occupancy until April? Or have the house under contract for the next few months, and then pay the bank directly in April when the seller is about to move out?  I don't want to pay the bank off, and then have the seller break the contract. But I also don't know how long it takes for the banks to process the payment to clear the foreclosure.