I can't say anything much about TalkTalk's package as I have never used them. I would usually assume that anyone who knows what they are doing can do better than a provider's package, but that may be a simple option for those who are not so knowledgeable or interested in becoming so.
As for Android devices though, the first thing to remember is that it's not Windows: the architecture is less vulnerable, and many of the threats you guard Windows against do not exist in Android. In particular there are no android viruses. That does not mean that there are no security threats, just that there is no self-propagating malware. In fact your biggest threat is "trojans", where malware is hidden inside an app that you install. So the first line of defence, far more important than any security app, is being sensible about where you install apps from: stick to the Play Store and you are unlikely to encounter malware, while installing apps from sketchy download sites that offer paid apps for free (i.e. already admit to criminal activity) or simply allow anyone to upload anything for others to install... well I'm sure you get the picture. The second line of defence is to be sensible about what apps you install: if a flashlight app is asking for the permission to read your personal information, access your location, install other apps, then either it was written by an incompetent who does not know how permissions work or it's up to no good, and either way you shouldn't install it.
Any "security" app comes a poor third after those 2 principles. To the extent that having used Android for a decade I don't have any such app currently on my phone. If you feel more secure for using something else then go ahead. But do avoid sketchy freeware Chinese "security" apps, especially anything developed by Cheetah Mobile: it doesn't matter how many installs it has, or how many positive reviews they've bought, a security app by definition needs the privileges to own your device and so you must ensure that it comes from a trustworthy source (and not a data-mining operation like CM). AVG will be fine.
As for the other products, Knox is Samsung's brand. I've always thought it was mainly enterprise-oriented (allowing IT managers to remotely manage devices, making it harder to root them) but have never owned a device with it. I have a personal distaste for McAffee after encountering their Windows product. But as noted I don't think you need very much on an Android device as long as you have some sense, so I'm sure either will be fine.