Death after RBD - then Designated Beneficiary/Participant dies after RBD

There are 5 Participants in Plan - Owner, her husband, their 3 over 21 and not disabled children.

Both Owner and husband began taking RMD's.

Owner dies in 2018, after RBD. Her husband is taking RMD's of her account.

Husband dies in 2022, also after RBD.

The 3 children are the beneficiaries for both accounts.

Looking to confirm what I think the new rules are:

Owner:

• 2022 - Paid as intended based on subtracting 1 from 2021 RMD factor used
• 2023 on - Must be paid by 12/31/32 to 3 children, using life expectancy of oldest son, then subtract 1 each year, w/bulk being the RMD for 2023

Husband:

• 2022 - Paid based on his age in 2022 using new table
• 2023 on - actually the same as for the Owner above

If the plan is an individual-account (defined-contribution) plan:

If something must or may be distributed based on a beneficiary’s life expectancy:

Could the plan provide for each beneficiary’s entitlement to be a separate share, so each beneficiary’s minimum is measured by his or her life expectancy?