The general name for that field is gerontology.
childcarer
doctors
traffic trigger
This is a manicurist.
Farmer or bison rancher.
Life guard
Grounds keepers
A parent/guardian
I would call them an aspiring veterinary nurse or an aspiring veterinary surgeon.
Someone who takes care of animals would be a Veterinarian. It could also be a farmer, or a zoologist. Even an animal trainer.
Building Custodian.
I think you mean a "Valet". (val AY).