cleanout plug drain

In the past, I have had grease trapped along a kitchen sink drain that was snaked out by a friend. I have an access to the drain before the p trap (which is in the floor... not ideal, but apparently code compliant in Ontario) through a clean out tee. I want to do it by myself the next time this...

I have a stub out in my basement laundry / utility room that stands about 2’ above the concrete slab. I’d like to cap this flush with the concrete (ideally without breaking out concrete). I’ve seen different style plugs or clean out caps (Tom-kap) that I think may do the trick, but my biggest...

I have a 4" cast iron threaded cleanout that is stuck. It appears to be very think. Are there any tricks to removing it? I have used liquid wrench and I have heated it with a torch. What's next? If I were to try to knock it out, what is the best method to drill into cast iron?