It might be helpful if you mentioned which state that you live in. Why is that important? Because if you lived in a CARB state, the answer is no. Only a CARB approved cat will pass.
If your state:
only performs an ODB2 readiness test.
The required number of monitors are ready
There's no visual inspection requirement or there is and the inspector doesn't put the car on a lift.
There is a reason why the Mustang uses 4 cats. The first set are called "light off" cats that are able to accept higher un-burnt fuel loads without getting too hot. This allows the 2nd cat to do a better job.
Expect to have a shorter cat life with only a single cat.