For the second question, i would define an atttribute on the host level and decide with the apply rule if the service get’s applied or not (as you already done that with host.vars.os)
Sorry this is defintely not working… if i update the service check as enable_nofitication = false i have been getting the syntax errors([2020-02-20 12:25:19 -0700] critical/config: Error: Attribute ‘enable_notification’ does not exist) during validation… If i update as vars.enable_notification=false thats not working…
Its enable_notifications as @fluxX wrote. I posted it before my first coffee
By the way, the docs are a good source to see what you can configure for each object type.