I think you are doing a great job. FBTs can handle a surprising range of temps and humidity levels, and they will let you know when you've hit the range they want. Your temperature is good-I would actually not go any higher than that. My toads did not like temps above 75 degrees. As for humidity, they love to soak and if they need to, they will hang out in the water dish. The bigger the water dish provided, the more chance for water to evaporate and raise humidity, so that is an option as well. In one of my tank setups, I used a huge glass bowl and then filled it with natural rocks and floating plants for my toads. It allowed for evaporation and my toads loved the space for everyone to join the pool party! Your toads sound very lucky to have someone who really cares about them. Kudos to you!