[Security Discussion] CHEF-KOCH:
First of all there is no security on Windows. People always making the same mistake, talking and talking about what software they use to improve something and forgetting one big thing, that there are a lot of proof-of-concepts, 0day and other possible attacks out there which can't be easily "fixed" by installing an security product such an AV. There are much known and also much unknown puplic attacks (and some 0day you can pay for) that working at the lowest possible level, such BIOS hacks, HDD firmware and partitions hacks (/TLDS/BACK/and such) that are almost impossible to identified for the normal user and even a professionals it's almost impossible or simply coasts a lot of time. And I know nobody which can spend the whole day to read everything on the net which could be security news related or is able to fix it, because lack of knowledge. Knowlage is even more poverfull than installing any AV or any other products which claims to "secure" something because if you know how the hacks working, you now how to defeat them (mostly without any tools), that usually starts with something like not install software which everyone use (like flash player plugins). Sure, it does not fix the fact that there are a lot of ofter vulnerable software out there, but the risk is lower because lack of hacker interest to infect something that is only used by a few people.

You definitely not need any AV on Android, Android isn't windows and even on Windows most stuff only works if you not use any administrative account. Same like under Android, there is a sandbox which normally protect apps from crashes/evaluation escape and other stuff. Of course there are some hacks and stuff which always works (some low-level attacks like certificate attacks, poisoning and such) but recently there is more and more a focus to get your private data or hack something that affects a lot of people (mentioned certificate hacks).

So the "best" someone can do is to read, read, stay up-2-date and use some brain to not install every plugin, not click every popup and not trust every app just because 1000 or more people use it (with five star ratings, even this never protects you against all stuff).

So there is and never will be any guide or recommendation what's safe and what's not. There are opinions and links/pages to read but the rest is matter of taste, brain, knowledge and tests.

Another example is that now people starting with Android 5 people more and more use the encryption but that does not help against data leaks or will stay safe forever.

My opinion is that Telegram and some other mentioned things aren't secure and there are several good reasons but people always want to believe the hype, but's my opinion. And to change the DNS is almost useless, Android uses default the google dns - why change to another DNS if apps like whatsapp, google play services constantly trying to connect to google (for e.g. ads, ping backs, sync,..)? To believe that DNS can't be attacked is a myth, there are several attacks, especially you recommend Firefox - but by default it uses his own DNS system (which needs to be disabled first via about:config).

AppOps is also only necassary if your ROM does not have the CM privacy Feature or a similar feature.

I not understand why you asking for e.g. a phone call blocking software, just use a black-/whitelist or simply go to airplain mode or shutdown the phone (shutdown the phone should be the best against known attacks).

But as said, instead talking about which app which guy prefer (which is useless) we should start a general talk how to secure the whole os and fix possible data leaks instead of taking all over again about something what is million times written on the net.