Yes, something like keywords could help, and personally I think it is best piece of meta-data to use for tracking characters, since it allows for plural assignment. The trick is that a search result (or a collection of any type) is actually a container in Scrivener, and thus you can do nearly anything with it that you would a folder. To access the contents of a search result in the main editor, just click on the Binder sidebar header (the one that is coloured in, if you have Collection tabs open there will also be a grey one at the very top). Now you can print that as a corkboard or outline from there (even Scrivenings, making this a viable tool for checking character consistency, for instance). Or, if you need more flexibility, you can also compile the search results or collections as a group, from the Contents compile option pane.