Figured I'd give an update a few weeks in. They are doing great, and they are way more active than in the smaller tank. I hear and see them jumping about all day. They use the upper ledges often (one in particular probably spends over 50% of the day on the upper ledges, while the others definitely use them daily). I really enjoy how much more active and seeing how their behaviour has changed. I definitely notice increased foraging.
Again, super happy I moved them to a larger viv, and I know it is on the care sheets that a footprint of at least 36x18 is recommended, but seeing the difference for myself has been eye opening. If you got your terribs in a small viv, upgrade them and you won't be disappointed! Keeping a bunch of open space has also been super good to see their massive leaps.
I suspect I've got at least one female (middle sized), as when I occasionally play frog calls it will sometimes hop around trying to find it. I think the other two might be one female and one male, as the largest one has very similar body shape to the middle sized one. The smaller one is leaner and has a sharper, more pointed back (which I'm told can be evidence of a male?). I'll try and get some photos. They are all at least 13 months now, so hopefully find out soon!