When we had cats, we'd train them with squirt guns.
Scratching furniture, spritz! Soon they learn and you don't even need water in the bottle any longer, just have a spritz bottle in the rooms the cats like to tear it up.
They were also not allowed on any furniture or tables UNLESS someone was sitting there, then laps were okay. Same theory, water bottle training.
We have never lived near any major roads that may pose a threat so our cats were always initially indoors, then Indoor/outdoor cats. No litter box once the transition occurs. On week long trips we'd just leave the door cracked in the garage, mass water and food, and their Kitty Condo outside in the garage.
They were always so thankful when we returned you could guarantee a few dead birds or moles or mice would be dropped on the porch the following weeks.
Another thing that never hurts when they're kittens is picking them up by the scruff of their neck. It lets them know that you're the momma and the cat tends to respect you more. It doesn't hurt them but rather in some cases is soothing to a kitten.
Nothing wrong with a cat kennel if you're going to keep the cat inside all the time and not be home during the day. The only issue with cat kennels is you have to start them young and ignore their pleas to be released in the middle of the night. They'll eventually quiet down but ONLY if you ignore them. They won't need a litter box inside the kitty kennel either. They won't poop where they sleep.
I had a Siamese that I trained to fetch a soft fluffy ball. People used to call him "Dog Cat".
