I missed that too. The second one looks MUCH better. I'd be a little concerned honestly buying a junk fan though. The fan becomes a VERY important asset, when it quits and you fry your whole crop it'll sure suck.
If you run a 400w with a cooltube you'll be aiming for what 6 -8 oz's? Your first grow usually pays you back for the cost of the equipment, but if you cheap out it could spell disaster. That carbon filter is probably worthless. I would think that a 400w light in your setup you need something that moves 225m3/hr, so shouldn't need a huge fan.
As far as filters you only need one the size of say the Can-33 filter. I don't know what that works out to over the pond, but they are kind of like half height filters. You could buy the cheap stuff online, but if they don't filter the smell and they don't cool the light, they may just be worthless.