This didn't get much attention when I first posted to low tech, so I figured I would give it another shot in a higher traffic zone.
I'm planning a modified Orinoco biotope for the future and am interested in comments/suggestions/critiques/and helpful hints.
The tank list consists of:

75 gallon tank

water ph ~ 5.5 - 6.5
water temp ~ 82 F

eheim 2126 pro II thermofilter w/spray bar
hydor circulation pump(s?)

dark sand
driftwood
pink granite

moonlight - in tank mount and waterproof
t5 48x2 - 2 (6500k x 2 and 6500k + colormax)

water lettuce - pistia stratiotes
red amazon swords - echinodorus sp. 'red special'
tiger temple plant - hygrophila sp. 'tiger'
brazilian pennywort - hydrocotyle leucocephala

green laser cory - 4 - corydoras aneaus sp. 'green laser'
orange laser cory - 4 - corydoras aneaus sp. 'orange laser'
huarani oto - 10 - otocinclus huaorani
electric blue ram - 4 (2 pair) - mikrogeophagus ramirezi sp. 'electric blue'
cardinal tetra - 20 - paracheirodon axelrodi
purple tetra - 20 - hyphessobrycon metae
marbled hatchetfish - 10 - carnegiella strigata

*maybe*
L-129 orinoco zebra pleco - 1 - hypancistrus debilittera


*back-ups*
rummy nose tetra - hemigrammus rhodostomus
green neon tetra - paracheirodon simulans


I want to do a low-tech/lower light set up so I went with plants requiring lower doses of co2 and light. I will probably be dosing my tank with Seachem Flourish and Flourish Excel to help boost the plant life. The modified component comes in when I introduce the hybrid plants and the color variations of the corys and rams.
Is there any concern that I would be over-stocked?
Is my filtration adequate?
Anything else I should be worried about?

I've run almost the exact same set-up in the past- it was attractive, stable, and easy to maintain. The only changes I'd make if it were my tank relate to fish stocking:
1) Reduce the number of species living in each tier of the water column to 1: Top, Mid, Bottom. The Otocinclus don't count since they're going to be on the glass and leaves.
2) I'd reconsider getting an orinoco zebra plecostomus if you want cory's. They need rock crevices to mark out territory, make lots of waste without eating any algae, and since they're slow and nocturnal, they will lose in food competition with the corydoras. If you're set on getting them, I'd skip the other bottom tier fish, make rock and driftwood caves for them, and use a higher capacity filter.

Those are my buzz words! Thanks for the input.
I would definitely forgo the pleco for the corys. They were one of the main reasons I wanted to build this tank. The other reason is the electric blue rams, I'm just crazy about them.
Which fish would you recommend for my middle tank level?