Hi Jedi
Do have a look at the implementation of SMTP in Simple Leave app in Joget Marketplace.
The app uses a Form to allow the user to set up the SMTP values without the need to access Joget console.
The form stores the values of the entered SMTP fields into 'Properties & Export>Environment Variable', which is in turn is mapped to the 'Properties & Export>Plugin Default Properties'.
The SMTP username and password is usually a "non-person" email address like 'info@gmail.com' or 'mailbox@gmail.com' and this is 'fixed' throughout the use of the app in production.
However, the "From" can be a hash variable such as '#form.table.email#' which you can populate in the form. But we usually fix it as 'donotreply@gmail.com'.
Hope this helps you 