IPhone – Streaming video from shared Mac folder to AppleTV

Even if the AppleTV functions without the HDMI connected, you will have no way to figure out what's going on when you have problems or when the AppleTV pops up a dialog such as the "Update available, update now or later?" dialog.

I suggest you sell the AppleTV and buy an Airport Express, which is designed to do what you're trying to accomplish. The Airport Express can be managed by any computer on the same network. Yes, you will lose a little money this way but you may find that it's no more than you plan to spend on the converters and cables for the AppleTV.

Further to Paul's comment, if you place your iTunes library on the remote disc it will work fine, but obviously you won;t have access to it when you are on the move out of range of your home wifi.

But you can create multiple iTunes libraries, and have one on your macbook, and one on the remote disc. Hold the alt/option key when starting iTunes to be presented options for creating/choosing an alternative library.

In order to stream from the library on the remote disc, you will need iTunes running, with the correct library selected. You will also need Homeshare set up both in iTunes and your Apple TV.

Good luck.