°should I feed it more than once a week? (Medium rats)
You don't need to feed adult male twice a week and you don't feed a male medium rats either, you don't need to feed anything larger than 75 grams rats once every 7 to 10 days. Feed too much and your BP will be more likely to fast or skip meals.

°is it easy to change its temperment? Or is it just striking due to stress
Yes by providing optimum husbandry and leaving the animal alone to adjust.

°how often do i mist?
There is no one answer for that, I never mist some people do, humidity should be around 50% however the substrate should nevert be damped.

°is it safe to live feed a mouse
Feeding live can be done safely if you know how to (I have feed well over 20000 live preys without incidents}.

Now if your BP take rats (since you mentioned rats) I do not recommend to offer mice unless you are ready and willing to feed mice from that point on and take the risk that your BP does not switch back.