1) It could work and may not work IMO. It depends on how it is executed, but the good probably would outweigh the bad, as you could play on the fact that they have experience in this area and know what to do. My guess is Edge TBH .
2) If it is a Midcard- Upper Midcard or lower, it would be best to build before getting the briefcase and while having the briefcase for a little while. But, if it is an Upper Midcarder or Main Eventer, a short reign would be cool, as it would create a bit of shock value. Look at Edge's reign in 2007 after beating Kennedy, it went for 4 days TV time and one day IRL.
2) If it is a Midcard- Upper Midcard or lower, it would be best to build before getting the briefcase and while having the briefcase for a little while. But, if it is an Upper Midcarder or Main Eventer, a short reign would be cool, as it would create a bit of shock value. Look at Edge's reign in 2007 after beating Kennedy, it went for 4 days TV time and one day IRL.