Touch id not working?

I have an iPhone 5s and my touch id just randomly stopped working and i don't know why. I have tried finding answers on the internet but none of them help.

Why do some of my messages to my friend not display the delivered message?

They don't say delivered or not delivered, it's just blank. The one above it says delivered that I sent two days ago but this one doesn't. This happens fairly often with this friend… I know her phone isn't dead since she's been posting and liking my photos on ig but it still doesn't say delivered under it. She has an iPhone 6s if it helps.

Is 16gb for an iPhone SE enough?

I want to get an iPhone SE and I was looking at the 16gb version. Is 16gb enough if I pretty much just want to use Snapchat, Instagram, some other small apps (probably not many games… And if I do get games, nothing intensive), and take a couple of videos (which I would eventually transfer to my computer)?

Added (1). I also might want to add songs (a couple hundred at the most… Definitely not near 1000).

Added (2). The other alternative would be the 32gb.

Instagram: Sorry There Was A Problem With Your Request

So as the title says i'm currently having problems with my (2) of my Instagram accounts. When I try to log in or create a new account it says sorry there was a problem with your account or your account has been disabled for violating our terms: http://instagram.com/...egal/terms. I have made a case with them but there not helping me with the issue. When I use my sister phone to log on my account it lets me log in or on my computer. But when I use my iPhone I can't log in. I have tried to uninstall the app and change my passwords and restart my phone. But nothing is working… Please help.