It's always hard, that time when you're in the thick of getting everything done that needs to be done, and the irrevocable certainty just continues to creep up on you apace.
There will be much that you miss. There will be much that you enjoy and appreciate in your new home.
Just let yourself feel, make sure you do everything you need to do, and see everyone you need to see, to feel that you are leaving 'in good standing', to use a very old fashioned phrase! (I also brought about a suitcase worth's of tastes of home with me - crisps, chocolate, sweets, condiments, soap, wine. . .)
And the kids will cope. Just make sure they get to say all their goodbyes, do what they need to do. We drew up a list as a family of all the things we were looking forward to, that we could refer to when feeling particularly down. They will have good days and bad days. Everyone needs to know it's okay to feel sad, feel angry, to be homesick - but this is it, and we're going to make the best of the opportunities and the new home we have.