If you are getting the puppy and theres no chance of backing out you need actual advice not berating.
Get your nanny on board, has she/he ever owned a dog? If I was your nanny I would be excited much to the shock of PP's. Puppies are fun and playful as well as hard work.
I would advise getting a pen or a safety gate blocking off a safe room like a utility room or kitchen where there is nothing to destroy.
I was lucky neither of mine ever chewed stuff up but for the first month i didn't give them the chance.
Leave the back door open all the time you are in the house and encourage the puppy to go out regularly.
Let the kids play with the puppy but also remember puppies sleep ALOT to begin with, make sure the kids don't keep waking it up.
Obviously vets for Jabs and Castrating, pet plans make this cheaper.
Get the puppy used to routine e.g. feed at consistent times, groom at consistent time etc.
You need to de-sensitise your puppy to new things e.g. hoover, new people, door bell, visitors etc. This will make them less anxious and barky.
Socialise your puppy as soon as they are allowed out, go to a training class,dog parks, meet up with friends with dogs etc.
Teach your kids to be gentle and teach them boundaries.
Prepare yourself for the first night the crying for their mum honestly breaks your heart. We allowed ours to sleep on the floor in our room, in a crate/pen with a warm teddy (microwave thing).
Once you get past the initial puppy stage if you do all the training and socialising you will have a chilled dog who you can take everywhere with you.
Trust me it is worth it!