To live and work in the U.S. for you and your family you will need to obtain a non-immigrant visa. The non-immigrant visa you obtain will need to have a dual intent which allows you to be in the U.S. with the intent to be here on a temporary basis while also filing a petition for an EB-5 immigrant status which is your intent to permanently reside in the U.S.
Probably not. The I-526 petition is an immigrant process (permanent residency). An entry you would attempt to make while the I-526 is processing would probably be a nonimmigrant process (temporary visit). Requesting non-immigrant status while an immigrant process is pending would run afoul of the dual intent rules. However, if you are already in the U.S. before filing you have the option of adjusting to permanent residency.