I never received feedback on this, so would like to follow up. I have learned since posting this that the Google Feed via Shopify's API will not push "Vendor" to the feed without having a "MPN" number according to support.
So my new, hopefully simplified question would be, can someone recommend a Shopify App that makes it simple to pre-pend or append the product Title with the vendor? I need this to happen within the shopify product database (not just the theme or liquid files) in order for the API to send the optimized data.
I am considering doing a bulk export, updating in excel using concatenate etc. then re-uploading, but 1) I don't want to break my site in case something goes awry with the upload and 2) if an app exists that makes this more straightforward, I prefer that.