That would pretty much be my first pass on this fix but I understand you want to make this look as pretty as you can. Then you are going to have to address the alignment problem with the nipple. It's fortunate that you still have most of the cup, in place. The last one I fixed had a large piece broken off. That one I chose to replace and then realign. .....You could just burnish out the intruding lip
have you pulled and inspected the lock. You might see something that needs additional attention.
Just a good general inspection and carefully operate the lock in order to understand how it works and look for any problems and clean. Rust has a tendency to creep in on the inside of the plate. Also, those two small machine screws can come loose. To date, all of the old ones I have worked with, look pretty nasty with dirt and rust. Yours looks exceptionally clean. .....Yes, but I don't really know what I'm looking for.
Also, those two small machine screws can come loose.
A very small drop of 'BLUE'(medium strength) Locktite on screw threads will cure this problem.