Don’t take my word for it but those blades look dented but useable. I imagine they would still be fine for producing useful thrust and could probably still work at full throttle.

There would be some slight wobble or noise but nothing that would destroy the engine (there is no mass missing so imbalance would hopefully be minimal). The safest course (and most likely to be followed) would be to shut down the engine and land ASAP, but if that’s not an option then use the minimum thrust required from that engine until landing and an inspection.

The engine would be rebuilt and very thoroughly checked for any hidden cracks or damage anywhere else (compressor blades, shafts, etc) and then probably just rebuilt and damaged parts replaced. New engines are insanely expensive but aviation maintenance can be overly detailed.

I guess if a spare engine is available the engine will be swapped out - every minute the plane is on the ground the airline loses money, and stripping the engine down and inspecting everything is a very long process.

All the rest I don’t know.