This, indeed, seems like the best way to proceed - especially because if you start with the three separate .pkg files, you might encounter difficulties installing iTunes at all.

Most .pkg files are built to contain a series of standard steps in which the package is first verified, then payloads are decompressed and copied to the target drive.

Suspicious Package is a free Quick Look plug-in which allows you to inspect package files (.pkg) on the Mac. Package files on the Mac are awesome, because they can install all of the various files ...

With Suspicious Package, you can open up any PKG file in Quick Look (select the file and press the Space bar) to peek inside and get a better understanding of what you’re installing.