You're welcome! ;)
As for ideas for the shoot, or things to think about...
Yes, a cloudy, overcast day can make for better photos than a bright, sunny day... but since you can't choose the weather, if it happens to be a bright, sunny day, try to get into the shade somewhere... shade is much better than bright sun... but your photographer 'should' know that... but something to keep in mind.
Your photographer should come well equipped to pose your family, as well as take lots of candid shots... often, those are the most adorable... I'm assuming you've already perused this photographer's work, and have a general idea of the kind of photos you can expect... thus the reason you chose them...
One of the most important things I can suggest is to RELAX!!! Let your photographer do his or her job, and wrangle your family into whatever shot she is trying to get. Don't get all photo-nazi and try to strongarm your kids to smile and sit still, etc... LOL (Not that you'd do that!) But seriously, try to trust your photographer... and let the kids relax and be themselves, even if that's silly, or shy, or whatever... your photographer, if he/she is good, will capture them at their best, and for who they are...
Have a blast!!! I love this stuff!!