What source are you quoting from? I had never seen this much detail on planned use of biological warfare or policies for occupation of the USSR. It's an interesting contrast with Nomonhan-Khalkhin-Gol, where the Japanese were not abusive of Soviet PoWs as we would expect from this era. That could have been a sign of a more enlightened occupation policy than described in your quotes...or not. Maybe it's just a matter of scale. PoW treatment in a situation you do not want escalate to total war could easily be different than a situation where you want total war.
The source is Anatoliy Koshkin, "Kantokuen: Barbarossa in Japanese" (Russian). Those specific excerpts are pulled from the wikipedia article and rely mostly on pages 21 and 22 of the above text.
Additionally, the treatment of Soviet POWs at Khalkhin Gol was uneven; there were many cases where Russians who fell into Japanese hands were tortured and killed on the spot. The lack of massive atrocities probably had more to do with the brief nature of the fighting and the desire not to provoke Moscow, furthermore they proved useful in later negotiations where they were swapped for Japanese prisoners.