Prepopulate node-add form with search terms? I would like users to be able to create band profiles (which will be a content type), and then those profiles will be associated with their user accounts via Entity Reference. However, I only want one profile per band, so I don't want each member of the band to be able to create a page for the band (but I'd like to have all members of the band be able to be related to the band page via Entity Reference). 

So, before a user is able to create a band profile, I want them to search current bands on the site (either via Views or Search API, not sure which yet...probably whichever method allows me to solve the issue below). If the band does exist, then the user will select it and a reference will be created. However, if a profile for the band does not yet exist, I want the user to be presented with a link to the node add page to create a band.

This is where my question comes in. When a user creates a new band, how can I populate the node-add form with the terms that they searched for to begin with? So if a user searches for a band from "San Diego, CA" called "The Band", how can I populate the creation form with "San Diego, CA" and "The Band" without him having to enter the information again on his own?
I don't know of a module that solves exactly the problem you're describing out of the box, but you might be able to come close with Entity Reference View Widget and/or Node Reference URL Widget.