First things first, wow you've got a knack for tank design, and holy bajeebaz that's a nice chunk of wood!!!
I put in duckweed and salvinia at the top, as I hope to discourage jumping from the fish I put in. Also my gf's cats will be a factor, I'm really hoping they don't mess with this tank as I'd hate to have to break it down.
If it's any consultation my cats don't bother with my tanks, I have hoods on them so the tanks don't get full of fur, and to discourage Rumpy (cat that eats things he shouldn't) from going "plant fishing" - the weird cat would rather try and eat the plants from my fish tank, than my fish from the fish tank!
Although I accidentally (acting before thinking) discovered a way to keep cats away from tanks, its a little risky, so if you try it, keep a towl and blow drier on hand.
When we were living with the in-laws one of their cats was always trying to get at the fish; one day I walked into the room and seen her on the tank, and instead of going and getting her off of the tank like usual, my brain made me take a different approach: stomp foot, clap hands and say "whatareyadoinupthere" really fast. Well she crapped herself and fell into the tank, so I rushed over, got her out and went to dry her off... Kind of traumatic, and not something I'd suggest as a first solution, but if you've tried everything and need a last resort, this works. She never tried getting the fish again after that. And surprisingly the fish were un-phased by the whole ordeal, the venustus was trying to nibble her toes the entire time she was in the tank, which was only between 5-10 seconds but as the cichlid people know that's plenty of time for a hungry cichlid to have a test taste! Haha