Razesdark

This plugin will allow all authors to have their own tweets shown on in the widget area of their posts, by adding it to their profiles. 
That way any multi-author blog can let their bloggers promote their own twitter account and not a joint account.

Author Based Twitter Widget

A Author based twitter widget, made to help multi author blogs have individual twitter widgets for their authors.

Frank Neumann-Staude

Ulf Schönefeld

polyres

This plugin/add-on requires the plugins FacetWP and Co-Authors Plus (WordPress plugin repository)!
This free plugin/add-on integrates FacetWP with Co-Authors Plus, allowing you to use Co-Author Plus custom fields for front-end search and filtering in a facet. 
With the help of Extend Co-Authors Plus for FacetWP, you can create a lable and choose the data source “co-authors” for your page or post.

Author Based Twitter Widget vs Extend Co-Authors Plus for FacetWP