Wow, just googled your bator. Is it one of those huge metal ones?!? COOL! First thing I'd do after cleaning it, is plug it in! I think it's a still air (as far as I can tell). Does yours have a fan?? As far as humidity gages, there are tons of different ones.
I use this cheap-o one from walmart. Not super accurate, but gives you a good ballpark estimate. I also like that it tells you the temperature highs and low in the last 12hrs. That way you can see if your bator is holding steady. As far as the stick thermometer, go ahead and calibrate it using the ice method and see how accurate it is. To do that you fill a bag (or cup, whatever!) with ice - stuffed, then fill it with just enough water to be able to get the termometer in there and shake it a bit. Plunk your thermometer in the ice water for a minute or two and see how close to 32F you get. Post results here!