A few thoughts... firstly that drawing is clearly not to scale
but are you sure you can fit two reservoirs side by side in the 800D? I've just looked over a few WC build logs for 800D's and it doesn't look like there's quite enough room. Also I'm sure you're aware but modding will be required to get a 2x120 res in the bottom.
Not sure if you need two completely separate loops anyway since you will get more than enough cooling out of 360 + 240 worth of radiators, even if you added a mobo block, and one pump can easily handle that. But then again WC isn't necessarily about what we merely need
, is it?
FWIW you can also feed both loops through one res if it turns out you can't fit both.
Also you will definitely
want to get aftermarket pump tops, firstly because the stock ones are ugly and unwieldy, secondly because aftermarket tops typically perform better and provide more options on how to route the tubing. Pretty much every company that makes watercooling gear makes pump tops so there's a lot to choose from. Also the MCP655 is just a rebranded name for the Laing D5, which again, all the watercooling companies sell, but be advised that using a top and pump from different companies might break the warranty on the pump. The pumps will take up two bays if that's where you want to put them, and obviously you'll need to either make or buy some kind of bracket. Most of the time when people put the pump in the drive bays it's as part of a res/pump combo.
About the rads... I'm not clear on precisely what rads you're getting, are they the new swiftech ones with or without the integrated res? I would recommend against the ones with the res since that's targeted more to the all-in-one kit market. Since you're building a full-on custom deluxe loop with your own sexy reservoirs you don't need that and IMO it will just make things bulkier and uglier.
As far as fans are concerned, it seems those rads are designed for medium to high speed fans. There are a huge number of choices but since noise level isn't an issue you should look at high-RPM fans such as the Gentle Typhoon AP-29. It would also seem a shame not to get a fan controller, have you looked into those yet?