Thanks very much for responding, jhan, but I've sorted this out. When I looked earlier, I completely missed a dmesg entry having to do with mounting disk partitions, which ultimately led me to the solution.
I have a pre-existing Solus installation on this machine. By way of preparation, I went ahead and used GParted to create my Funtoo partitions in some unused disk space. I also added a data partition at this time, which could be shared between Solus and Funtoo. At the conclusion of the partitioning and formatting, I ran $ sudo blkid from Solus and copy/pasted the output, so that I would