Hi!
Appending results between results is not really possible by configuration, but might be possible with a custom code.
Sponsored post
I have made a custom code that may work. I have tested it in few cases, but please be careful. Change the $id variable to the post ID you want to add as sponsored, and the $position variable to which position it should be.
Add this custom code to the functions.php in your theme/child theme directory (copy from line 3 only!). Before editing, please make sure to have a full site back-up just in case!
Variation name
As far as I know there is no such thing as variation name in WooCommerce. The product/variation titles are requested from WooCommerce itself, if it is filtered, it should return the vaues set in the database.
Is this perhaps a custom field that is set separately, or another feature, let me know, I can take a look at it.