I see you have a lot of visual equipment on your list (eyepieces, diagonal and Barlow).
For astrophotography you won't need a diagonal, and if your like me, your eyepieces will only ever be used for aligning the finderscope during the day. I do have a diagonal, but it came with the scope. You may need an extender though to reach focus without a diagonal, but they are a lot cheaper. A 50mm extension tube is a few dollars, compared to the $100+ for a diagonal.
My suggestions would be to ditch the diagonal and all but one (or two) eyepieces, also ditch the barlow as its almost useless for imaging and the ED80 doesn't have great focal length so planetary imaging isn't a good idea on the scope. ED80 excels at DSO (nebula and some galaxies).
With regards to the focuser: The moonlite is great. Do you think you would want to motorize it in the future?
I ask because it is a lot easier (and slightly cheaper i think) to purchase the focuser with motor attached from Moolite than it is to attach it yourself. Its abut $700/shipped for the motor version (with PC controller). Something to think about, not a necessity.
The scope is fine. The autoguider is a good choice as well.
Right angle finder: this is a personal preference but i found a red dot finder to be better for astrophotography. If your going to be doing visual then stick with the right angel finder. The red dot finders are pretty cheap ($35 from bintel) and simply put a red dot at where the scope is pointing. If you align it properly while there is still light then it can be very accurate.
Light pollution suppressor: wait until you have a month or two under your belt before grabbing a filter. You will have a hard enough time learning the ins-and-outs of the mount without worrying about a filter
Field flattener: I haven't used a William Optics flattener with my ED80 but i have used a HOTECH - SCA Field Flattener and Televue TRF-2008.
The Hotech is purely a field flattener where as the Televue is a field flattener and reducer (widens the field of view).
Both work well, although the Televue is a bit expensive in Australia at $399. Its cheaper from the US at $282. The HOTECH is a little cheaper at $245 US. Just providing some alternates.
Mount is fine. The HEQ5 is what i started out with and handles an ED80 perfectly fine.
2" UltraWide Prime Focus Telescope Adapter $79+freight
This concerns me. The field flatteners i mentioned, and the William Optics PFLAT4 all use a standard t-thread. This adapter is an ultra wide adapter, which is larger than a standard t-thread. You won't be able to use a field flattener unless the field flattener is made for wide adapters.
Instead i would recommend this (or any brand/similar equivalent):
http://www.bhphotovideo.com/c/produc..._for_Sony.html
With that adapter your image train would look like this:
Scope -> Field Flattener -> T-Ring -> Sony Camera.
One other thing you probably havn't thought of is a power source for the camera. Do you have multiple batteries that you can swap out? My Canon goes through a battery every ~2hrs, with the back screen turned off. You may be able to get an AC adapter for the camera so you wouldn't need to go replace the battery all the time. Ebay has them normally for a few bucks from China.
