Hello. I'm just getting back into the aquarium hobby from about a decade away. I am new to Discus. I am setting up a new tank and I would greatly appreciate any suggestions on bio-load, substrate, plants, filtration, etc., etc., etc.,

I would like an Amazonian-ish fish bio-type, low-tech show tank focusing on the Discus preferences, but I will be cheating on the bio-type with the plants. I would prefer easier plants that do not require me to dig around in the substrate alot. I'm okay with root tabs but I would prefer not to mess with CO2. So it does limit my plant choices. Here is what I was thinking:

Specs:
75 gal. 48 x 21 x 18 lightly-planted aquarium (only non-negotiable)
Temp: 82 F
PH: 6.9
O2 levels >8.0 mg/l
Hardness: 2 degrees (for plant growth)

Fish:
5 Discus
8 Silver Hatchetfish
2 German Rams (mating pair)
12 Neon Tetras
3 Corydoras Sterbai (groundskeepers)
2-3 Otocinclus cats (for algae control)

Lower-maintanence Plants:
Amazon Sword (Echinodorus bleheri) centerpiece
Cryptocoryne Beckettii
Anubias Nana
Dwarf Lily
Amazon Frogbit or (carefully monitored, but cover for hatchetfish)

Filters:
Fluval 305 Canister Filter (260 Gph)
Tetra Whisper EX70
Emperer 400 Bio-Wheel

Two HOB filters might be a bit of overkill, but I got them cheap, so I figured I might as well use them. The Emperer 400 is dying, so I will probally need to replace it soon. Suggestions? Maybe in time I can upgrade my canister.

Heaters: Two Aquatop Quartz Glass Submersible Heater (300 Watts)

Substrate: Seachem Flourite (for plants) mixed with a small gravel substrate (more for aesthetic purposes)

Anyway, any suggestions on on bio-load, tankmates, substrate, plants, filtration, etc. would be greatly appricated. Thank you for reading!