I don't really have an opinion on the poem. That's up to you, though the original version and the more recent version have vastly different meanings.
I'm assuming the first change to pg. 6 is from Yukari's line in the third panel, but I disagree with the change, because it alters the meaning. The way it is, Yukari is wondering if autumn will last longer than normal because they had a longer winter. With the change, she's wondering if the longer autumn will mean they'll have a longer winter. Depends on what the original text says, but the meaning is pretty different.
Your change for page 9.4 flows a lot better, so I think that should change.
For 13.1, again, that changes the meaning entirely. As it is, she's just stating a fact (i.e. that there are lots of fruits and seeds), and summer can't just transition straight into winter. With the change, she'd be saying there are lots of fruits and seeds, and you need those to get through the winter. According to how arcrenciel translated it, the first meaning is closer to the original text.
And on pg. 16, thanks for catching the typo. Sometimes I wonder how I can miss these things.