Cases for Telescopes

As you don't have extremely fast telescopes and thus only a rather narrowbe am of light, the 32mm-prism should be sufficient and not cause any vignetting.
The alternative to the 32mm-prism would be the Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B) # 2456095 with 36mm prisms, which we recommend for the larger Mark V (Giant) bino-viewer, because that binoviewer has got larger prisms than the Maxbright II. But with your telescopes and the MaxBright II, the smaller 32mm-prism should be fine.

This will work for fine focus for visual use. Focus is adjusted by rotating the upper ring, this gives you 6mm of travel.
For photography, you may want to consider the back focus distance of your telescope:
https://www.celestron.com/blogs/knowledgebase/what-are-the-optimum-back-focus-distances-for-celestron-scts
So you may want to use some T-2-extensions for a DSLR.
Anyway, for focusing a DSLR, you should better use a large focuser like the 2" BDS-SC Baader Diamond Steeltrack® Focuser # 2957220. A 1.25" focuser will cause vignetting with the large sensor of a DSLR, as 1.25" is smaller than the sensor of a DSLR. We do not recommend a 1.25"-connection for a DSLR. (Bonus: You cn attach a motor focusser to the Steeltrack, which ist great when you are working a camera and a computer)

The EdgeHD800-reducer is made for a backfocus of 105mm.
You need this distance for the complete setup, including the back focus of you camera, all adapters and the length of a ClickLock, if you use it behind the reducer. The #2956220 SC / HD (2")-Clicklock (5" SC, 6" SC/HD, 8" SC/HD and 9¼" SC) has got a length of 47mm.

Thanks for your kind words on our products!
We're assuming that by "Twistlock" you mean our 2" ClickLock clamps? In that case you can simply purchase our #2956242 M42i x 0,75-ClickLock (Astro T-2 System), which you can thread directly onto the T-2 thread of the adjustable top ring.
https://www.baader-planetarium.com/de/zubehoer/adapter-foto-zubehoer/okularklemmen/baader-2%22-clicklock-okularklemmen.html#574=955

Unfortunately we don't deliver directly to customers in the USA, so if you want to purchase, please contact our distributor www.alpineastro.com

That's correct as long as you don't use filters.
The RCC has got a backfocus of 91mm, minus 20mm for the filter wheel and minus 6.5mm camera back focus leaves you with 65mm.
But a filter moves the focus point by ca. 2/3 of its thickness outwards, so for a 2mm thick filter, you should add another 1.6mm, e.g. with our Set of T-2 Fine-Adjustment rings (0,3 / 0,5 / 1 mm) - Aluminium #2457910, or one of our variable T-2 VariLocks # 2956946 or # 2956929
So, with a 2mm-filter, you are at ca. 66,6mm which need to be bridged with extension tubes.