Matthew we're not getting the Carbon Fibre OTA just the aluminum OTA.
We have much of the other equipment you mentioned already as we use the 40D on our Skywatcher 200mm Newt.
We already use a Power adapter, shoestring USB, PHD guiding and use the Canon software for long exposures and live view for focusing. And also on order Losmandy Dovetail Bar and Bob Knobs.
I'm sure there will be many more bits and pieces we will need as we get going with the SCT. It's seems a never ending spending spree once you upgrade to something different
Thanks for your input
David