While I do see a ton of information here, it is kind of all over the place. To get back to the original question...
"Does my aquarium need to be cycled if I stuff it full of healthy plants from the beginning?"
Well, no one hear really loudly said it, and I want to at least get it out there, in case anyone new reads this thing: You could very easily lose all of your fish trying to cycle with live fish, relying on your plants to do the filtering.
Hey, I've done it with success, before. Substrate in, plants in, fish in, turn on equipment, monitor parameters, cross fingers, hope. I've also seen entire tanks of fish die off, due to an ammonia spike, even though the tank was "heavily planted". There is too much gray area there, for my tastes. What is "heavily planted"? How many fish to use per plant? Per ounce of plant? Per stem? Per surface area of leaf? Seriously, there is no real way to quantify the needs for this process.
In short, I personally judge it way too risky, and stick to fishless cycling, even in my heavily planted tanks. Could it work? Sure. Does an entire tank of fish slowly dying of ammonia poisoning cause you any angst or sadness? Measure that (unknown) risk versus the potential gains, and make your decision.
-- 2.5 Gallon mini bowfront with a field of crypt wendtii, some java fern, java moss, 8 RCS, and several species of snails.
-- 55 Gallon long with Green Rotala, Crypt Wendtii, Red Ludwigia, Blyxa Japonica, Bacopa Carolinia, Banana Plant, Dwarf Sag, and an Amazon Sword. 2 Bolivian rams, 2 German Golden longfin rams, 2 German Blue Longfin Rams, 17 Rummies, 7 Neons, and a lonely Amano.