I'm having trouble clearing a moderate clog with my snake in a bathroom sink drain just downstream of where the ABS transitions back to 1950's-era cast iron drain pipe. The photos show the work done eight years ago during the bath remodel, the cast iron as it drops below the floor, and where it connects to the shower drain line.

My snake gets caught up just under the house where the pipe makes a 90 bend and I'm pretty sure that's where the clog is too. I'm able to pull some hair out but sometimes my snake gets snagged and it takes some time and patience getting it freed up.

My plan is to cut out the 2" cast iron between the elbow and where it connects to the shower drain, snake upstream to clear out the clog, and replace the pipe with ABS (two-way clean out) and fernco fittings. However, if I use a snap cutter do I run the risk of compromising the cast iron hub connections and then have leaking joints? I've cut 4" cast iron before but can't remember how the hubs/bells responded. Any thoughts would be appreciated.