Yes, still running the iron based catalyst and it seems to double to triple the miles between a regen, which is a very good thing. I have no way to measure if there is less soot in the EGR system, but logic would say there is less.
DEF has zero to do with the particulate filter regen. The regen uses fuel to heat the DPF to ignite the soot and turn it to ash, which mostly exits with the exhaust.
The diesel exhaust fluid, which is water and urea, is injected before the SCR catalyst, to react with NOx to produce N and O2. The consumption of DEF is supposed to be directly related to how much fuel you use. From what I've seen that is true.
This is widely misunderstood, even on the diesel boards. The DEF has nothing to do with a DPF regen.