You know, what this may do is just make things a bit easier on you anyway. The fish load on the bacteria will have dropped about in half and this will do two things: it may make it appear that you're cycled, when in fact the "feedback" you are getting may in truth just be a little harder to detect (when the amount of ammonia is very light, there will be little periods of time when you might measure zero but then other periods when its not zero and you can't be as sure when only measuring every 12 hours or whatever.) Also, the overall process of getting the size biofilter you want will be slowed a bit, as you will have to acheive some of it via fish introductions later on.
But all this can be good. The best thing to do is work on getting your tank (plants, etc.) to look again the way you want and try to enjoy the 3 fish left. Keep testing and water changing just as you have been but now you'll be able to enjoy longer periods between necessary water changes probably. Once you get a string of days where the filter is keeping both ammonia and nitrite(NO2) at zero without you changing any water, say 3 days, then you'd actually be clear to add back, say, 2 new fish. You're at a stage now where its hard to predict whether you'll see that string of days right away or whether you'll again begin seeing some traces of the toxic chemicals and have to water change.
~~waterdrop~~