Finally, I decided to plant the four healthiest seedlings in one big pot, and just be content with a large plant with dark glossy leaves. Then last spring I put the pot outdoors, mostly to get it out of the way.
This is what happened:
Clivia blooms from one of four separate plants in the same pot. Three different views.
I'm curious to see if any of the others bloom, and what the colors will look like. According to the seller of the seeds, the parent plant had dark orange, nearly red flowers. But even if they are the usual orange, like the blooms pictured above, I'll be happy. The plant will be happy too. It has a nice spot in my kitchen window this winter, with good soil and regular watering.