How much of a time skip was this chapter? One year or two years?
2 years
No. (Almost) 4 years have happened. The story started in 2015, you can corroborate this by looking at the few calendars that appear through the series. By chapter 44, it was either end of December or the first days of 2016. The career seminars that Yuu mentioned don't happen in the first year of college in Japan. Yuu is at least in her second year, which should happen in 2019. It could be 2020 too, but that's too further. Making the story start in 2015 and end in 2019 both in-universe and in real life seems very Nakatani-like in my opinion. Oh, and the month should be October, since the Cultural Festival is taking place.
Yagakimi still hasn’t totally ended since it’s still has short story compilation as a part of Yagakimi Curtain Call Project... soon.
This announcement and the artbook one are the only ones that don't have the Yagakimi title in them. Of course the artbook will obviously have ygkm illustrations, but I don't think all the book will be about it. It's only stated as "Nakatani's artbook, title undecided yet" , same with the short stories. Given that all the other annoucements including the artbook will feature yagakimi, I do think one of the short stories will be about yagakimi, but all the others won't. I may be wrong and maybe none of the stories will be about it, though.