show_quick_panel docs:
items may be a list of strings, or a list of string lists. In the latter case, each entry in the quick panel will show multiple rows.
However when having multiple lines per result, the quick panel only fuzzy searches over the first line and ignores the rest. Is there a smart way or flag to have it also include the other lines?
CMD+P for example also fuzzies over the filepath and not just the file name inside the quick panel
This is not possible at the moment. You may want to show your support for this feature by upvoting the following issue:
Yes please!
My orgmode refile feature wants to display a lot of information and it would be handy if the user can search in all lines of text.
I have directory, filename, full heading path within the file. That is far to much to cram into one line ESPECIALLY with how cramped the quick search panel is (I wish I could tell the system to make it the full width of the window) Right now I am seriously considering implementing my own search window since the quick panel just really is not flexible enough to make this very important feature elegant. 
Any improvements to the quick panel would be a big boon.