Amazon Echo - Questions about multiple users in same household

Factual Questions
1

Scenario: One household, one Echo, one husband and one wife, each with their own Amazon account.

Can H&W share an account while still maintaining separate accounts?

For instance, can they each maintain their own to do list, but share a shopping list?

I know both have to set Echo up independently…then what? Say, “Alexa, go to Husband’s account” and then add something to H’s to do list? How do you get back to the shared account to add eggs to the shopping list so eggs will appear on both H & W’s lists?

Can voice recognition help here?

Thanks for any guidance.
mmm

2

See this article, in particular near the bottom. According to this, you can set up separate accounts, and then identify whose account you want to use verbally (rather than voice ID):