In situations like this, we always chose one person to be the "resort" person. They made the ressies (and requests) and paid the deposits. The "other" party just gave the deposit money to the "resort" person. Once you check in, each room is counted as its own entity, therefore, each party can pay the bill to their own room. Charging priviledges work the same way. Each room has its own account, so the credit card used for each room can be different. My brother and I did this with our families a few years ago.
Now, as the other person said, requests are just that. If both parties arrive at the same time, I am sure a request can be made upon arrival and you could get connecting rooms just as easily (if available) as if you gave request upon reservation. I would think arriving at the same time would be the important factor.