Yato, Congratulations on your Clivia's first blooming. I'll go through your questions from the top down. #1, The seed pods yellowing and dropping off soon after the plant blooms simply means those flowers were not pollinated, and did not produce a viable seed. The one that is still green may produce seed, or may not. If the plant was growing inside all winter, there was probably little chance that any of its blooms got fertilized(pollinated). If you are located in a warmer climate, and the plant was outside some of the time, a bug may have pollinated the flower for you. If you were closely examining the blooms as they opened, you just may have managed to transfer pollen to that flower. Since you say this is your only Clivia, if you do get a viable seed from the pod that is still green, it will certainly be a selfing of your plant, and any offspring of a selfing usually produces plants/flowers that look very much like the parent plant, unless your plant is a "long line" hybrid, then the "grandparents" genetics can come into the picture.....I digress, so back to the subject.

#2. Don't worry about increasing your collection of Clivia plants, your plant will take care of that problem for you. They bloom best when they are pot bound, so don't worry about repotting it yet, because they also produce baby plants best when they are pot bound. I don't know where you are located, but if you have warm summers, take the plant outside when danger of frost is past, and put it someplace where it will get partial shade, and watch for baby plants to appear in the pot. The little plants will sprout from the bottom of the main plant, and from the roots. Let the plants grow until they are pretty large before you take them off. Taking the baby plants off means you will have to repot all the plants, including mama. I wouldn't expect you to get more than two or three babies off this young plant, but I have taken as many as 10 little plants off my large mother plants at one time. You will be filling your growing space, giving away/selling Clivia plants for a Loooong time.

#3 Putting the plant/s outside during summer will surely produce seeds for you. The flowers will drop off, and the little pod will grow to about the size of a large cherry. As it matures it will will turn a rusty reddish color, and eventually become soft . Remove the seed pod, and open it up. It should contain from one to four black roundish seeds. Plant them and watch them grow.

Enjoy Bill