Like i posted earlier, her common route was mostly about her not understanding what love is. Which is also accentuated slightly later, in which Yuuki finds out she has been getting confession at a daily base but she has been rejecting all of them.
Her actual route was primarily about her new invention that effects the mood of people because it gives off a a nice smell or whatever it was. It helped Yuuki securing his spot in the 3rd place by 800 (?) votes in the prelimaries instead of the usual 600 in the common route.
Later before the first round of the elections, Non-chan turned that machine on again to attract more people during the campaign and something went wrong and it gave the reverse effect for the people around them and it almost went out of hand. After the first round, Oojima ended up being last and Non-chan blames herself for it.
Eventhough Yuuki managed to completly win the 2nd round without the help of Non-chan's invention but with good preparations, she was still a little depressed from earlier.
To cheer her up, Yuuki decided to have a"date" with her (conveniently the others couldn't come, so it became really a date for the 2 of them) and at the end of the date, he confesses to Non-chan (the development to this was like i said earlier weak, because there was almost none) but she postponed giving an answer because it was rather unexpected for her (and for myself as well).
2 or so days later, Non-chan did not show up for the usual promoting Yuuki's campaigning. After a short moment the group finds out that Non-chan has gone to Moheji's side. Which obviously shocks everyone for her "betrayal" and it hurts their campaign as well, because they don't have their instant stage for promotion.
At the end of the day Chisato saw that Yuuki was the most effected by this and after confirming that Yuuki was indeed in love with Nozomi, she gives up on Yuuki and encourages him to believe in Non-chan and talk with her.
So Yuuki heads off to Non-chan and she explains that this "betrayal" was somewhat a blackmail because of her machine from earlier.
It didn't help that this ended up being lazily resolved, so i completely gave up on the plot at this point.
As for the final speech, it was entirely skipped. You saw the group cheering for Yuuki before the speech and it skips immediately to the aftermath..
After congratulating Yuuki for his efforts and hard work, the group decided to leave Non-chan and Yuuki alone. After that there was a short talk between the 2, which ended with Non-chan answering to Yuuki's earlier confession with a kiss.
The epilogue shows Yuuki, now a 3rd years and the vice president, with Non-chan bringing him an actual handmade bento prepared with love (which was a small event in her common route related to her not knowing what love was)