Ideally you should specifically bequeath the ARF to your spouse (so it doesn't just fall into the "residue") .
On death, the ARF provider will likely require proof of bequest (perhaps Probate) before transferring ownership.
Once Probate is granted, it should not take long, a matter of a few weeks.
Thanks Conan,
What I wondering is whether, after probate is granted, the new ARF must be put in place (in the surviving spouse's name) within a certain amount of time. The surviving spouse would ideally prefer not to be subjected to the imputed distribution this year if possible.