Why won't read messages disappear from my notifications tab?

I've had the iPhone 6s for exactly two weeks now, and I'm continuously having this problem. One or two random texts messages a week won't disappear from my notifications tab, even after I read it. I click remove, it stays. I slide to the left and click the x or reply, and it's still there. After I turn the phone off and on it goes away, but I don't want to have to keep doing that. Any suggestions? Is this happening to anyone else?

Should I get an iPod Touch 6g or an iPhone 5c?

I currently have a plastic LG Blackberry to text with and an iPod Touch 4g for everything else. It's become obsolete now, so I have the choice of either:

a) Getting an iPod Touch 6g and keep using the LG to text with (Since I don't call anyone or have data anyways).

or

b) Getting an iPhone 5c and throw out the plastic phone, effectively combining the two.

The only concern I have is the lack of power in the 5c, and if it would support iOS 10 whenever it comes out. But I don't want to be that kid that pulls out his WannaBerry (that's what my friends call it) to text people. I do text a lot as well, so it's a really hard decision. Any thoughts? I'm 16 btw.

IPhone 4s deleted texts without backing up?

I have an iPhone 4s that I need some deleted texts and pictures from. I didn't back it up or sync it to the cloud before I deleted stuff. Is it possible to recover the info? If so-how?

Why does my iPhone 6 alarm clocks not go off?

I have 6 alarms set; 5:00 am, 5:20 am, 6:45 am, 7:00 am, 7:15 am, 7:35 am. All of them are set to go off every weekday. I depend on them to get up super early for showers and whatever. Well sometime they don't go off, and I thought maybe they were going off but I was turning them off in my sleep but today I was laying in bed, not asleep but with my eyes closed and waiting for my 6:45 and it just never went off! I checked and it is set for every weekday. And it's not the volume because the 5:00 am one I heard and my 7:00 am one I heard Why does my iPhone 6 alarm clocks not go off

What app can I use to download videos from YouTube to my iPhone 6?

I like to download YouTube videos a lot but can't seem to find any at all for my new iPhone 6 if I can't find any I'm returning this phone and going back to android phones I just need a site or app that I can post the link to and it'll immediately download to my phone

Are the IPhone 6 and IPod touch 6th generation cases the same size?

Would my iPod touch (6th generation) be able to fit both hard and soft cases made for IPhone 6's, or would only soft cases be able to, or neither?
I've heard soft cases from the 5th generation iPod touch cases can fit, however I've also heard that hard cases crack and in addition can damage possibly the iPod.
Simply put, does this apply to the iTouch and iPhone, or are they both the same size?