Sharepoint - Set "Allow management of content types?" set to "Yes" within a Content Type or List Definition

This can be done either by setting EnableContentType=true in the list definition or in the feature activation event we can set the attribute. Please refer the below links. They will definitely help you in solving your problem.

Enable managing content types by default at list creation

Creating SharePoint 2010 List Definitions in Visual Studio 2010

A Quicker Way to Create Custom SharePoint List Templates

This says to "toggle the SPList ContentTypesEnabled property from False to True".

Just toggle the SPList ContentTypesEnabled property from False to True. That enables the use of multiple content types on the list.

EnableContentTypes="TRUE" instead of EnableContentType="TRUE" (note the s)