That size mouse should be okay for now, though I generally like to keep the mouse/rat weights as close to 15% as possible.(I breed rats though so its a little easier for me to be precise). I know that in most scenarios a hiding snake is a happy snake, but some are a little more brave then others. I'd double check your temps to make sure theyre on point but my girls come out exploring at night fairly often, or to get a drink of water even. I have rubber frogs quarium sealented to the sides of my tanks and sometimes they'll even coil around those for hours at a time whether it be the warm or cool side.