No, 1-1/2" vacuum hoses are the least common and most vacuums sold today come with an adapter to change the hose sizes.
Unfortunately it does not unless you buy a $0.31 3/4" x 1/2" Schedule 40 PVC Reducer Bushing. This fits directly inside the Drainado then it will connect to 1/2" PVC pipes.
Yes, most vacuum hoses can simply be flipped around so the flat end that normally fits into vacuum port and the tapered end will slide into vacuum port instead.
Yes, Schedule 40 & 80 PVC pipes have the same outside diameter. Since the Drainado fits over the outside diameter of each pipe, it will work for both schedules.