Re: R. imitator froglets
I haven't bred imitators but I've raised a lot of tads and baby froglets and what I have found is that the more air exchange they had the quicker their carriage and motor function tightens up. Oxygen blood levels are basal to all functions and perhaps there are oxygen regulatory mechanisms in the lungs and skin that need to stabilize in what is arguably, a frogs most dramatic somatic state.
I realize this may sound out of the box and in contention with what / how many people have done it with collective and multiple thousands of froglets in the hobby, but Im sharing it. Its only fresh air, a little more may be worth trying out for anyone who may be curious to note their own observations and results.