First, compliments to Gambit for getting out in winter and opting for the too often neglected Sheltowee Trace in favor of more well known sometimes beaten down crowded trails such as the AT, LT, and JMT.
These posts most aptly describe my leather hunting boot experiences attempting to make non WP leather boots into somewhat WP boots using lanolin, mink oil, beeswax, or other pastes. I'd always vigorously work in such pastes to seams but in short order the boots would absorb dirt and would only be WR not being able to step into a puddle or hike in slush very far before socks became wet.
Although not a general fan of WP shoes, in cold winter conditions with mixed ground conditions around freezing I find them acceptable.
Another option I've found some success in winter is spraying leather boots with a nano particle spray such as Tarrgon. It reduces mud, ice, water build up on leather boots while providing WR. I've never found myself able to make a non WP leather boot into something that's 100% WP. Despite claims it can reduce some breathability but in freezing conditions if all what's going on with the foot system is dialed this isn't perhaps as critical compared to warmer months. It needs to be reapplied so often. That's why I often combine it with an insulated Seal Skinz or Hanz WP sock electing to carry two prs of socks with different traits maybe a merino winter pr and WP sock.
https://www.tarrago.com/product/high...otector-spray/ Good news is the ST is not a muddy trail based on my 2X SOBO thru hikes of it finishing in late fall. BTW, I experienced about as many natural arches on ST thru hikes as a Hayduke Tr thru hike that went through Arches NP!