I don't know how you get these ideas, but they're great. Some of them are doable with, I think, the help of a smartwatch. Like the "save us from a stroke". The watch can monitor our vital signs and tell Alexa if something is not right.
"Provide Security". Another good idea. I will change the safe words for something that don't arouse suspicion, if an unwelcome guest is in the house. Alexa then could call 911.
Don't need to change voices on "Call my mother". Alexa could tell mom that we're busy at the moment.
9 and 10. We could only wish...