If the lather is starting to dry during the second or third pass, you can always add a bit of water to it by wetting the tips of the brush and then going over the lather again. But it might also be that your lather was too dry to begin with. That can easily happen if you overload the brush. I already add tons of water to my lather and I only load for 30-40 seconds. If I'd load my brush for a minute, I'd be working my lather and adding water for more than 10 minutes I think.
If you think your lather is too thin on the second or third pass, you can try to squeeze out a bit of lather from the brush, then apply it to the tips of the brush and paint it onto your face. But like I said before, I don't care that much about volume after the first pass. I still want a bit of volume, but nowhere near my first pass. I do want my lather to be slick though and not dry and pasty especially after the first pass.
So in your case I would probably try two things. Hydrate the lather like you're hydrating it right now, but load the brush for a shorter period of time. See if that helps. Or load the brush like you're loading it right now but add more water to the lather. I want my lather to have a nice sheen to it.