Welcome to the forum,

I could go on for paragraphs but I won't . . . the answer to your questions is YES. With a little clarification re: the melody question (as it won't fill in "exactly like the record" melodies" but if you want it will fill in "a melody")

I purchase the harddrive as it serves as a back-up "just in case" but over the past decade or so I have never had a "just in case issue."

Bottomline, run to your phone and order as soon as you do that you will start being blown away with your results.

PS: While I do very little with Realband I understand that in itself it is a pretty darn good DAW. Others sill chime in.

Later,