I think, as is often when this type of topic comes up, that we're mixing apples and oranges and not offering a direct solution to a specific issue.

Greg, if you're asking in general (and I'm simplifying) if you need a sequencer, the simple answer is yes.

If you want to record and arrange music at home with individual tracks you're going to need some application to do that.

BiaB comes with Real Band. Audacity is free. I happen to use Acoustica's Mixcraft.

There are a million out there and the choice is yours.

Then, how to specifically integrate midi files into the DAW is a separate issue.

Hope that helps, - Mark