Oil from the past leak on the injector loom can run down the engine loom & cause oil to contaminate the crank sensor end, but you can usually see this easily.
Ref a floating crank, if they are worn that much you can push/pull the front pulley & see a lot of movement, so worth a try.
Non genuine crank sensors are rubbish, so watch out for them if used.

HTH
regards
Steve