peewee vs django for DB processing
Use of peewee in Django is totally OK. Actually I recently did a project like that. But I still recommend using Django ORM if you do not have some particular reasons to use peewee. 
Here are some issues that may occur when you use Peewee in Django:

You may need to write your own db middleware and testcase base class to make django work with peewee.  
A lot of django open source apps will not work any more because they depend on Django ORM.
Migrating tables in Peewee is more difficult than Django ORM.

But Obviously Peewee also brings something good:

Stand alone Database processing module, if one day for some reason you do not want to use django any more in a project, it could be very easy to reuse all these peewee code.
It is much easier to make two or more projects use the same database if you use peewee. And the table structures are totally under your control.

And maybe more. So as conclusion, I would say Peewee is great, but it is still not working perfectly with django now.
Working on a python & Django project with mysql (newbie) 
Trying to figure out if it is preferable to use peewee in the python DB part & Django models in the Django forms or go ahead and use Django for the entire thing
Related answers claim that Django is high overhead but could not find a base for that assumption
Thanks,
Shimon