We are only 50 miles from the Gulf Coast, so quite a bit warmer than Kansas.
I intentionally let my first crop go to seed and harvested a whole baggie of seed. But I have not had to replant due to the volunteers.
We use the cilantro, parsley, and dill at our restaurant. I harvest a bit different than your suggestion -- I use kitchen shears and cut about 3 inches above ground - within a week, I have more harvestable produce.
i have not had luck with growing cilantro and i just love it--will try again this year--oh and i like rice in my tortilla soup --i like to add that little pack of yellow rice (can't think of the name now) --but have made recipes using enchilada sauce which was really good too and one even added a package of ranch dressing and that was great--i love making salsa too--as for your brother not liking cilantro-i heard martha stewart say she doesn't like it and my husband doesn't--i guess it is something you love or hate because i just can't imagine not loving that fresh taste!
Cilantro self seeds and laughs at frosty weather. My grandchildren love it. They call it "the herb" and head to my herb patch to nibble on cilantro as soon as it starts to spring up. We all think it looks good, smells good and tastes good. mmmmm!
I just love cilantro in fresh flower arrangements...it's a sweet little filler flower and you sure can't beat the smell! My raised garden bed is getting dismantled to make way for a new potting shed this summer, so I'm going to try raising it in pots on the deck this year. But rest assured, once the shed is in place, my landscaping will be raised herb and veggie beds all around it!!