I've just gotten off a Zoom call with a literary agent who's shown interest in this. It's not a conversation I was expecting to have this soon, but it sure feels like a promising sign!
My takeaway for the time being is that I have a few more things to put together before it's ready to take to a publisher, with or without an agent representing. I haven't had a chance to catch up with my writing partner in person since finishing the artwork, but I'll need to do that soon so we can celebrate that milestone and talk next steps. He's the kind of writer who prefers not to plan too much in advance, but it looks like we'll at least need an overall story outline and chapter synopses so publishers can get an idea of where things are going.
Apart from that, I've been speaking with other artists locally to gather opinions and advice from as many sources as possible. The consensus for now seems to be I'm best off aiming for publishers based in the US who have lots of experience with graphic novels, since there really aren't any big players in that space here in Australia, and selling graphic novels is quite a different challenge than other children's books.
It still feels like I'm just getting started, but the road ahead is looking a bit clearer. I'll keep you posted, crew!