I cut the stalks off my elephant garlic before it could flower, which is supposed to make the plant put more energy into forming the bulb. Maybe this is why your bulbs ended up small. The immature flower stalk is tasty in stir fry.

I'm afraid your replanted bulb might not make it since when you dug it up, you probably tore off most of the roots. You should probably leave the rest of the plants in the ground until they are more mature.

The little bulblets can be planted, but it takes longer for them to grow than the cloves from the main bulb. I'm saving mine and will plant them, but will probably eat them as green garlic.

Keep in mind that elephant garlic is not a true garlic but is actually in the same species as leeks. If you leave leeks in the ground long enough, they will also make similar bulblets around the base of the main stalk.

You might want to read up on leeks to see what to do with those seeds. I have never heard of people planting elephant garlic seeds, but if you want to try maybe you can treat them the same way as leek seeds.

You could do two things:

1) cut the scape (use it in cooking) and leave the rest until the stem gets soft,
falls down and leaves turn yellow and dry up. And then harvest.

2) leave the scape alone, let it grow bulbits, let them develop until the plant
falls down and the leave get yellow...just like case 1. You could then plant those bulbits.
What will you get? Perhaps a single clove/onion garlic. You could then use it or
plant it in which case you would get a normal multiple clove garlic.