I have been working with various e-commerce clients to increase their sales as well as their brand awareness. As per my experience, social media ads don't give better ROI considering overall sales, if you are selling any product or service at the same time social media can do wonders in case you are doing brand awareness campaigns. On the other hand, google searches are always intent based, you can target people those are specifically looking for particular product or service, in your case, it's mortgage services. For your campaign, our main focus would be on google ads to generate leads, along with that we can run facebook campaign by creating the similar audience using the data captured by Facebook pixel. Successful online campaigns cannot be determined based on ad managers past experience but it depends on how much time he is investing in optimising the campaign to increase your ROI. For further discussion feel free to message me.