I'd discuss mealtime planning with them, if you are all going to cook together then no point having two gas stoves, two gas bottles, etc.
Something I've always found when going away with other families is that they may need something (extra tarp in wet weather, a can opener) but you might too. So having that discussion beforehand is always worthwhile.
And speaking of the extra tarp, I alway have additional tarp/s, ropes, pegs and poles, you never know whether you are going to need to jury rig a sun/wind/rain shelter, or just set something up for some additional privacy.
Taking lots of firewood and alcohol will ensure that if you do need to lean on your friends they will be happy to help out in return for some of your hospitality