All my guys have pinkish legs from time to time from rubbing against the glass when they burrow or from moving across the substrate. When my first one ever passed from edema I remember her legs and belly went redder then usual, I don't think your frog had redleg. For the cleaning I will be honest and others may disagree but I only do a major disinfect about once every 3 months, before that I just do a super hot rinse and that's it. If your frog isn't sick and your changing out the substrate once a month or every 3 weeks you shouldn't have a bunch of bacteria living in there. A really good product is Zoo Med Wipeout, this is what I use to disinfect. For the substrate being wet, your supposed to squeeze out most the water so there is really no reason to leave it out to totally dry. A good rule is you want the substrate to clump in your hand when squeezed but not dripping water, this is what they need and it helps with the humidity.