From picture 1, it looks like the flange can be separated from the drain body. In picture 2 while holding the drain body from the bottom of the sink, I tried to remove the flange with a plier by twisting the flange counterclockwise. The flange did not budge. In picture 3, it shows that there’s a protrusion for the lift rod that prevents me from lifting the drain body straight up. I don’t have a power saw. It seems impossible to remove the drain body and put in a new one. What can I do at this point?
Take $15 and get an angle grinder from harbor freight.
Before I had any tools I use to mess around with hand tools like hacksaws - what a joke and a waste of time.
Buy or make a close quarters hacksaw. If it has a pistol style handle, turn it around so it's opposite the teeth. Carefully cut a slit in the flange, then grab the flange with pliers just as in your second picture, crumple it in on itself and push it down through the hole.
While you're working on this cover the drain tube with a sandwich bag using a rubber band to hold it on, to prevent sewer gases entering the room.
Pull the drain flange up like in your second picture. Insert a large screwdriver through both holes in the pipe for leverage and use your Channellocks or a pipe wrench to turn that flange counterclockwise while holding the screwdriver firm. If that doesn't work, cut the pipe from the bottom with a hacksaw