New 6x2x2 tank set up questions

Hi all,

I've recently purchased a new 6x2x2 tank. I've started to put together all of the equipment for the new set up, and I'd love some feedback as to whether I'm heading in the right direction.

Lights
Currently I have 3x 72" 10000K LEDs on order through Build My LED.
I've been considering getting one 6300K (instead of one of the 10000K ones), so it would be 2x 10000K and 1x 6300K to show the reds better, because I'm going to have a few red plants in the tank. Do you think that's the best option? Or should I stick with 3x 10000K?

Filter
I've got 2x Eheim 2075 on order, which will be plumbed into the bottom of the tank. Also running 2x 300W inline heaters. The guy at the aquarium shop suggested one heater would be enough, because they're really efficient, but I think two would be better. Any issues with that setup?

Substrate
I'm thinking of going with CAL Aqua Labs Black Earth (you can have a look at it here). I would use 4x normal bags for the base, then a few bags of the finer stuff for the top layer. Does anyone have any experience with this product? Would you recommend adding anything to this substrate?

CO2
Any recommendations on which CO2 setup to get? The reactor I'm considering is Sera CO2 Flore Active Reactor 1000. I'm open to suggestions!

Fish & Shrimp
I'm looking at keeping guppies, various cherry shrimp, and some kind of schooling fish (tetras or similar). I'd love to get some Australian natives as well. Does anyone know of any native fish that would go well with guppies and shrimp? I'm hoping to order through AquaGreen because of their native selection, and I've dealt with Dave in the past and he's been fantastic.

I'll definitely be starting up a tank journal when everything starts coming together in a few weeks.

Thanks so much for your help!

Cheers,
Kurt