You can take your newborn baby to the beach but not during the hottest times of the day. Babies are sensitive to heat and sun; therefore, you must be careful about their safety at the beach.
A family of five can normally stay in one hotel room. You just need to know what to look for or become more creative.
Taking enough formula shouldn’t be an issue when traveling in the car, but if it’s by plane, there are restrictions on how much prepared formula you can bring.