There is a simple solution to add new tasks with the help of Alexa to your MLO inbox:
a) define an MLO email address - any email send to that address will show up in your inbox
b) define an IFTTT activity - trigger is "Alexa, add item to todo list" and as action you can use gmail to send to above address
c) Then use Alexa to add an item to your Alexa todo list.