I wouldn't get super carried away and flatlock everything. I did a flatlock trial a while back, and almost everything that I just straight flatlocked has popped. I mostly made nightgowns and underwear. None of the underwear held up with straight flatlocking, and the nightgown that I didn't serge first didn't hold up either. I have a few pieces in the mending pile as we speak. The nightgown that was serged and flatlocked has held up beautifully!

I think the fleece might stand a better chance of holding up mostly because you don't put the same stress on those seams. I can't wait to hear how it holds! I think I will go update the other thread.