Need advice on really long fishless cycle. The problem - lack of nitrates

After 80% water change I did 25% change and then 25% change next day again (I was still keep adding NH4Cl targeting 2-3 NH3 ppm). Nitrate reading was still around 20-40 ppm. Finally I did 70% water change, Nitrate dropped to 5 ppm.
But now with cleaner tank I have less bacteria so the 12-hours ammonia level (measuring ammonia in 12 hours after adding NH4Cl) raised from 0 to 0.5 ppm. 12-hours NO2 is 0 ppm and NO3 is 10 ppm.

Now I'm getting ready for the fish again - dropped temperature to 78-80 degrees, dropped water pH to 7.00-7.10 while keeping KH around 2-3, keep adding small amount of NH4Cl (targeting NH3 1.0-1.5 ppm) and waiting till 12-hours both NH3 and NO2 level drop to 0 ppm.

BTW dropping water pH to even 7.1 AND KH = 2 degrees was the hardest one - my tap water is 9.4 (as I've already mentioned)