Her good credit doesn't cancel out your bad credit, so if you are on the mortgage with her you'll still need to meet all of the waiting period requirements. There are loan programs out there that are OK with a recently discharged Ch 7 BK, but they have increased down payment requirements (i.e. less than 1 year requires 35% down, etc.)
Correct, your income cannot be used if you are not on the loan.
How much (%) would you be putting down on the new home?
How much are you estimating property taxes & homeowner's insurance to be on the new home?
What do you plan on doing with your current home? How much is the mortgage payment?
What are your wife's other debt payments?
The answers to those questions will help determine if her $47k/year of income would qualify for the new purchase.
If you need to be on the loan with your spouse in order to qualify for the sales price you desire, but can't qualify due to either the FHA, VA, USDA, or Conventional BK7 waiting periods, you can always go NonQM/Portfolio. These loan products are viable alternative for people who don't fit into the box. Rates and fees are a higher, but there are no prepayment penalties so you can refinance out of these as soon as you're able. These loan have 5/1, 7/1, 10/1 ARMs as well as 30 years fixed options. Hope this helps.