1) Correct, you are subject to the 10-year rule.
2) You must fully drain the IRA by then end of 2032 (based on your wife's year of death, 2022).
3) Because your wife's mother died after her required beginning date for RMDs, under the proposed regulations you are subject to annual RMDs by continuing your wife's distribution schedule.
You must take your wife's 2022 beneficiary RMD if she had not already done so. Note that the RMD factor for 2022 must be refigured due to the updating of the Single Life Expectancy table for 2022 and beyond. This means that the 2022 factor generally will not be the 2021 factor minus 1. The factor for 2022 will be the new factor for 2019 reduced by 3.
Also, using the age of the oldest beneficiary was only required if the original IRA was not split into a separate inherited IRA for each beneficiary by the end of 2020 or if the beneficiary of your wife's mother's IRA was her estate or was a trust that was not qualified for look-through, otherwise the RMDs would be based on your wife's age, not the oldest beneficiary's age. Still, with the account required to be drained by the end of 2032 and tax rates scheduled to increase in 2026, it might make sense to distribute more than the RMD each year so as not to have a large spike in income in 2032, perhaps pushing even more of it into years 2022 through 2025 than you would with equal distributions over 10 years. Also consider that you're still be able to file jointly for 2022, so it might make sense to take out even a bit more in 2022 to take advantage of MFJ tax rates.
