@Arnold is not wrong, but they're also almost impossible to kill, so great for learning and experimenting on.
Benjamina cuttings root VERY easily. As long it's actively growing, and you see that white sap when you cut it, you can stick it straight in a pot of soil, and start watering like it's a tree and in a couple months it'll start growing like a tree. You can make yourself 20 new trees in a day, so not shortage of material if you screw something up.
I've personally not found them to be finicky, but I've seen enough out of mine that I can understand how people feel that way about them.
My best friend thought it would be interesting to make three canopy style clumps out of the leaves. So kind of train three levels of leaves into pads. I thought it was a pretty interesting idea.
Your thought here seems like it would turn into more of a topiary design than bonsai, but you could play with the idea some.