Although we can't offer investment advice, click this link for an article containing a section on IRAs and Estates. 

The article mentions that Traditional IRAs could be rolled over into Roth IRAs (a taxable event) and that beneficiaries can roll over an Inherited IRA to their own IRA account.

[Edited 04/02/2020 | 12:06 PM]

If you do that it will all become taxable income to you.

To avoid probate and estates, you can name one or more primary or secondary beneficiaries to each IRA and specify the percentage each beneficiary is to receive, then the RMD amounts (or more) would go directly  (and be taxable) to the beneficiaries but under the new tax laws must be totally distributed within 10 years.

You should each have your spouse as the primary beneficiary.

Always name someone (not the estate) to be a secondary beneficiary of your IRA. This eliminates any complication. 

The only tricky part is the executor must be able to find the person named.