I'm not sure, but I'd guess the answer is no - it shouldn't mess with the mini cycle.
When I put my clown goby in my established QT (or so I thought) for hypo, I experienced a little ammonia spike, but after three days of water changes, everything was back to normal. Then, I started dropping my salinity.
I expected problems with my biofilter (Biowheel 100) with the lower salinity, but it never happened. No trace of ammonia/nitrites ever reappeared. Seems like it didn't effect my biofilter - that's why I'm guessing it won't slow down your cycle.
One good thing is that at the lower SG
, I think the fish metabolism slows down as it doesn't have to work as hard to regulate the osmotic pressure between the tank water and it's internal fluids. For the same reason, I think they eat less too. It seemed that way with my goby. All those things seem to help you out in controlling the ammonia once you get the SG