Hi, smart search function is Joomla core function and Phoca Cart finder plugins only add information for the Phoca Cart products and categories. I think, in smart search you need to remove old manually with the emptying prompt.
Phoca Cart System should be enabled (it is needed for Joomla mail template integration). User plugin and webservices plugin could be disabled if you don't need such features.
Not sure, what do you mean with: "Phoca Cart Finder Plugin (Products with images)", there are only two types of finder plugin: products or categories.
Jan