CiviCRM Entity, Display tags name in contact
I need to add an option "Tag ID" in the Host Source Column field setting of the CiviCRM Entity Reference module to make this work. 

It won't take much to add it. 
Look in your code to the matching file, add:

'tag_id' => 'Tag ID (Entity Tag)',

https://github.com/eileenmcnaughton/civicrm_entity/blob/7.x-2.x/modules/civicrm_entity_reference_field/civicrm_entity_reference_field.module#L148

Then you can add another CiviCRM Entity Reference Field to the Entity tag entity type:
admin/structure/civicrm-entity/civicrm_entity_tag/fields
Target Entity: Tag
Target ID: Tag ID
Host source column: Tag ID (Entity Tag)

Set this field to render in a view mode on the entity tag manage display area:

admin/structure/civicrm-entity/civicrm_entity_tag/display

This will render the tag entity, you can configure which fields of the tag entity show by configuring a view mode and configuring to use it on the render

admin/structure/civicrm-entity/civicrm_tag/display

Now back at your Contact, make sure and render the view mode of Entity Tag, that renders the right view mode of the Tag entity, and you'll be rocking.

I will add a PR to CiviCRM Entity to add the one line of code necessary to make it work out of the box, but it may be a couple weeks before the next release goes out.