I would wait and see if they will adjust the wording of the contract. If they think that it won't work and will use your email as your 2 weeks notice, then I would contact the other family and let them know why it was not going to work out (basically the other family). That if they are interested in finding another family for the share that you would be happy to work with them, but you will not do a huge list of things for the family that hosts the share and have the other family not be a true equal in it.