Yii2 advanced template

I have a fairly large website in terms of models that i’d like to rewrite in Yii2 as a personal project ;D

I think the best way to describe it is a kind of buying/selling website. Sellers tends to be more businesses than individuals and the buyers are more so individuals. So I had a few questions:

  1. Looking at the template, perhaps the back end could be for buyers who write and administer adverts.

the frontend for general users? I would like as it’s a project to build some REST functionality, would it be advised to create another application called “app” for the REST part of my website. I did read in the guide that it was advisable to separate it from your main application.

  1. Would you create 2 user models as the users have very defined set of roles? I didn’t in my previous Yii 1 version correctly I think. But am seconding guessing now if they are working in different apps.

  2. Where it says in "getting started" set the document roots for the webserver, where are you setting them?

  3. How much do things like Giiant, where you can rewrite models, negate the need to do migrations are your DB changes?

Thanks for the help in advance!!