Good Morning Bama Baby,
You know better than anyone if these family members are the kind who pitch in and help or require you to play the hostess. Also does your husband help out? Are the children generally well behaved or are they kind of wild? Are they independent for meals since you will be eating much less and may not be able to tolerate regular food by then? How do you feel about eating differently from the family, will it bother you? As long as they understand that you may not be feeling "wonderful", and can be understanding and non demanding, and take care of themselves you may want them to visit. If, however, you would rather wait until a time when you can fully enjoy their company I would ask for a different time of year.
Good luck on your journey.
Joy