For now, I think I'm going to try working with ArangoDB. The decision is based on a few things, but is a short- to mid-term decision. I like their command line interface for working with graphs. I also like that the database is so flexible: it will let me do other features, such as user account management, without needing a separate database. It also seems to be pretty stable and scalable for my initial needs. But I'll be keeping an eye on Dgraph and a few others in the meantime (and maybe even a blockchain graph solution in the long run?).