Well, no need for laterite as said.
Zeo and Purigen work well
Water change routine will do well.
I'd do perhaps a split system for CO2. A DIY CO2 in line Reactor, not hard to make, cost 10-15$ and then a disc in the tank near the out flow of a filter.

Then blast the mist around etc.
CAL Aqua labs makes an in line disc diffuser that's pretty cool and runs on 160 gph or less.

Venturi might be a bit over kill for smaller tanks and not get the best usage.

The disc only cost 10-20$ for a Rhinox 1000-2000 model.

Lights: I hope you can turn off 2 of the T5's there. 2x 54 w T5's over a 75 is plenty of light for many designs and layouts.

It's fine to have more, I just want you to have the option to reduce/increase lighting.

The permangnate dip is fine that you use for fish for plants.
I'd do an alum dip as well.

(Alum)Aluminum sulfate can be bought at most bgarden centers. They sell it in liquid form as water clarifier in our hobby(Eg Mardel Labs etc). 1 table spoon per liter ought to kill most things. It's somewhat acidic. If you do the dip, then dip in lime water, that will kill most things, do this for 1 minutes or so.

I tend to not bother.
I rinse the plants in tap without the dechlorine, leave in there for 2-6 hours.
Then add the plants.

Fish: I feed them the medicated food to kill the parasites in a quarantine tank.
3-4 weeks: add them.

Regards,
Tom Barr