I brought the chain tool and hex socket set today and made a bit more progress.
The bolts holding the crank arms to the bottom bracket came off easily enough. They were 8mm, so I could have done them yesterday with the hex key. I just assumed they were larger and didn’t even check. Once the bolts were off, though, it took a bit of persuasion with a hammer to get the crank arms off the spindle.
The tool for the bottom bracket itself will arrive tomorrow. (It’s a different style from Kuroko’s.)
I also removed the handlebar and stem. I haven’t yet decided if I’ll reuse these bits. If I do, at least I’m going to cut down the bars a few centimeters, as they’re too wide. With the stem off, I thought the fork should just slide out, but it wouldn’t. I may need to loosen up the headset cover a bit. I’m going to go gently, though, because as far as I know I’ll be reusing the headset.