OK, we asked and you responded promptly, so I guess we owe you an opinion.
You like convertibles, then! Personally, they are not my favourite, not sure how robust the hinges and the cables that pass through some of them are - but I've never had one.
I would suggest you get along to somewhere you can have a hands on test with the machines, some laptops these days have track pads that drive me to distraction! I'd recommend a wireless or bluetooth mouse for when you are in your home/dorm.
Any one of these machines should handle the work you suggested. The Core i3 isn't the fastest processor in the world but it should be handle what you mentioned but probably not games. An i5 would be better but probably breaks the budget.
To the machines, The Lenovo Yoga is quite an old version and for extended use, I really think the screen is too small. I rate that 5th on your list.
The Lenovo Flex also uses the older Haswell processor and that may not produce a full day's battery life. In other respects, it's reasonably up to date. The warranty is not as good as the other machines, so this is 4th on your list.
I'd rate the Asus and Toshiba equal second. They both have the 5th generation processor, the Asus only has 802.11N wireless, the Toshiba has the more up to date 802.11AC. It also has, for a laptop, good speakers built in. The Toshiba warranty isn't great. Do checkout the Asus trackpad, I have a full size Asus and the three finger trackpad is horrible!
Which leaves the HP in 1st place. The specification is up to date with the latest Intel processor, which has a very good battery life, the B&O sound system is good for a laptop and the warranty is reasonable. I'm surprised that the specification doesn't include gigabit Ethernet but other than that, it looks to be a capable convertible.
All my personal opinion, I'm sure others may have a different preference.
Disclaimer: I'm a "Baby Boomer" rather than a "Millennial" and so a bit more of a traditional PC user!
Hope this helps.