Can there be any Django wordpress plugin or multiple-use application available that people may use to include online directory feature to the Django based website?

You won't find something of that nature, because using django means it can be done with only a couple of lines of code on your own. Django isn't a Content management systems, but a framework, and that means you is one level much deeper. Many of the things where you would employ a wordpress plugin inside a Content management systems are typical tasks for django developers, so there actually is no requirement for a wordpress plugin to show such stuff while you pointed out.