Yes, there are lifeguards on the beach. They are not Disney CM's . I think they are on duty from Memorial Day thru Labor Day.
They are usually on the beach by 8:00am and one responsibility is to set up and rent beach chairs and umbrellas. They also have beach bikes available to rent.
The ocean temps from June-August are in the mid 80's (unless there is some sort of storm offshore that brings in colder water).
I was very nervous about getting a HH reservation for June at the 7 month window, too. But it all worked out. Got a 2BR for 6 nights. Had to call day by day.