C.E.
I have a 3 year old that I am stil childproofing for. We have locks on our top cabinets fridge, freezer everywhere. As your son grows just try to stay a few steps ahead. I would definately move the cat food/water to a counter or somewhere as my 11 month old is always playing in the dog water at grandmas house and it is more of a safety thing than a mess. You also dont want him eating cat food and risk choking. What we do (and tell all our guest ) if youthink your purse or whatever it is is high enough off the ground go 2 more feet. At 6 months its probably not a problem yet. Also if you have a fireplace make sure he cant open the doors, and if there is an edge or corners they do make rubber pads to protect the edges as he will probably start pulling up soon too.
It sounds like you have done all the safety stuff you need for now, and with every stage you will find more. They sell baby locks for everything now, including toilet paper, toilets, ovens you name it its out there. I get most of mine at target and its made by the brand Parents and is a red package.
Good luck