For the food mishap, here is what I do when I leave town and have someone watch my tanks....
I take those little round glad-loc containers and add some RO/I water to them and then place in all the food(s) that I want fed in that sitting... So for my tanks I will have X containers for how ever many days I am going to be gone, plus a few extras... If you feed twice a day then have 2x per day plus a few days worth extra (just in case)... Just place them in the fridge and have your "fish sitter" just open up the containers and pour it into the tank... On my FW setups I use the wkly pill holders (7day ones) and I put in the flake/pellets that I want fed on a given day so all they have to do it open that day worth and pour it in...
If all they have to do it open and pour, they can't really mess it up, as long as they do it when/how often you say and make sure that if they miss a day not to add the one they missed and the current one at the same time (unless other wise specified)...