Check in question

We will be traveling with another family this Oct & we will more than likely arrive at BLT before our non DVC guests. Will we be able to check into our rooms without the other family being there yet? Since we have already purchased our park tickets from another source can we go ahead & have concierge meld the park passes onto the room key cards without them being there as well? Once they arrive is it possible for them to change their room keys to have their own purchases charged to their cc instead of ours?

I'm pretty sure you can check in without the other people but unless it has changed you can only have one credit card. We wanted to split it with my sister in a 2 bed but couldn't in 2010. Not sure about the park tickets as we tend to use APs

We were able to have 2 different credit cards with our Key to the World cards in Oct. 2011. My husband and myself on our credit card and my sister and her husband on their credit card. We were on the DDP and ALL dining credits went into a joint pool that any of us could draw from though. We were in a 2 bedroom villa at OKW.

In my experience, I've always checked in for my entire family as long as we're in the same room regardless of when we arrive. The front desk will give you the room keys for all in your party. You'll have to get keys to them.
Yes, they can go to the desk and put a credit card on their key. Interestingly, I was at a resort where other guests had done this. I was listening to a conversation of cast member with the guest whose name the room was in as the main desk. One of their party's credit bounced, so he was stuck with the entire bill.
I don't know about melding the parks ticket with your key-to-the-world if you purchased it from another vendor. I would think they would not do that. I would think you would just use the passes you purchased. I have an annual pass and just carry it with my room key. Enjoy BLT. It's a great resort.