Just my opinions...
1) I think you need to get a much smaller tank for now (10gal) Once he is an adult he will be ok in a 40gal as long as it is cluttered up a bit. BPs dont like big spaces, they want to be cramped a little.
2)You need an under tank heater, they make them appropriatly sized for the size tank you have. With the 40 I would suggest 2, one on one side for a 40 and on the other side one for maybe a 10. You will also need a Tstat to control the heat.
3)Heat lamps kill humidity, you are always better off if you can control temps from the UTH. Covering 3/4 of the screen top will help hold humidity as well. Misting a couple times a day will help. Get a thermometor with a digital humidity reading, too high humidity can be as bad as too low.
4)Yes...that will also help if you are having humidity problems. Mulch, aspen, newspaper, that overpriced pet store bedding will all work. STAY AWAY FROM PINE AND CEDAR.
5)I use tongs, I hold the rat by the scruff of the neck so the snake can get a good strike. Always monitor the strike and coil until you know the rat is unconcenious...so he wont bite your snake.
6)My rule of thumb is a week. Put him in his new home, observe him regularly to make any nessacary adjustments but no feeding or handeling for a week.
7)Big water dish, 2 identcal hides one on warm side one on cool side, Tstat, thermometor w/ humidity reading, I would cover 3 sides of his tank with cork board (this will help with heat and security) UTH, snake!!
On a personal note...I would reconsider getting my new snake from pet smart and buy from a breeder, you are more likely to get a healthier, well started snake. Also keep in mind, most BPs will hide during the day and cruise their tanks at night... A hidden snake is a happy snake. I would also suggest feeding in the late afternoon hours.
Hope this helps.