Please, could you explain what do you mean with ‘initialise the token’? Do you mean to create a template by microflow?
You could create tokens needed for your Email Template in ASU.
In my application I have a TaskToken which has to be filled with Task name when sending email to users.
This I have called in my ASU. Ofcourse MxModel reflection should be working.
Then replace your tokens when sending email. I have a module called TokenReplacer in my project. Not sure if it is available in Appstore or if it is inbuilt.
This is how I have done this and its working fine.
Hope this helps.