Fostering can be a very rewarding experience
and well done to you for taking care of your friend's dogs. You've gotten some great advice so far, I just want to add a few things. I foster puppies and dogs for welfare all the time - our latest one, Charlie, is proving very, very hard to let go!
Anyway, you didn't mention if the dogs knew each other? If they do, that will help a lot to make them comfortable living in the same house.
Before the dogs come to your home, I'd have their crates and beds set up for them so that they can settle in right away. Also, take away all the toys and then start introducing the toys again slowly, starting with the least interesting ones first.
When the day of the move comes, have your friend bring her dogs over and then take all the dogs for a walk before going into the house. This will help establish them as firm friends and then you can simply walk them into the house together. And once they are inside, they will have their things & should be very happy to stay with you and your dog(s).
If there are any issues between the dogs, let them sort themselves out. Don't interfere because it will only make it worse. If there are any tense moments, the best thing to do is to walk away. They will follow you and the tension will be broken.
Good luck
I'm sure you will have a lot of fun with her dogs!