There was mention in the movie that half a section was 80 acres. This is incorrect. A section is 1 mile by 1 mile. Homesteads in Kansas were given out in quarter sections or 160 acres. Half a section would have been 320 acres.
I don't care what state you are in. A section of land is 640 acres. The site you linked simply says the government was giving away 80 acres without stating it amounted to a quarter section.
I knew of some cases where a man and woman would claim adjoining quarter sections and built a cabin on the line between their claims. The cabin would have a walled partition but they could claim they were separate living spaces. You could build your residence any place on your homestead. This helped you get twice as much land. I have a feeling most of these people ended up married.
Yes. In her letters Elinore alludes to the fact that it was more acceptable that they be married since she was if marriageable age. There was no doubt affection and being married worked well for her. Plus he doubled his land. I believe he did build a cabin for her in the land but in reality they lived together.
Many couples married at first meeting. The women came out strictly to get married. Have babies and start over.