without posting any links, Ill let ya'll dig:
-all water that is aged has tons of bacteria, mixed heterotrophics. filthy amounts, and a huge portion is nitrifiers. a large, significant portion of the mixed communities in the water on floc and various aggregates are nitrifying bacteria. find the links, they will either prove or disprove it. links exist for both
yes it instant cycles, every tank Ive ever built was done this way, I dont cycle, I opt out. reefs included. There is an ammonia risk however, associated with large pockets of organics mid decomp in the mud/bed
disturb that, get an ammonia cycle but much of whats said about the bacteria has actual bacteria disagreeing. they are everywhere, especially in bodies of water, some free floating, most associated with biological aggregates in the water. things that filters catch and hold...your bacteria was not affected in any way, in fact the disturbance of ammonia will temporarily increase the BOD depending on how much organics was xferred over due to a temporary bloom, then back to steady state depending on the variables of the newer tank.
the recent study on advancedaquarist.com about bottle bac is one huge good read about bac
any ammonia we see in moving tank situations is from disturbed organics+ammonia greater than the current balance of nitrifiers set to the continual amounts of ammonia in the water column, its not dead bacteria unless meds factor into the equation somehow