I and my wife both have iPhones (iPhone 4 and 4S). I wanted to know what app(s) should i consider to be used in our phones for anti theft measures ? I am considering the situation where i have already lost the phone (or it has been stolen) and i want to ensure that in best case i can get my phone back and in worst case, the phone is unusable to the person who gets the phone.
Now from my limited know how about the inbuilt security measures and 3rd party apps i have few queries..

1. The 4 digit passcode lock is the most basic type of protection so that no one can enter your iPhone. But what happens if i myself forget the passcode or someone enters the passcode wrong too many times. Consider that i have disabled the wipe data thing after 10 attempts. Is the only way to retrieve the phone usable from this state is DFU restore ?

2. What 3rd party apps can i consider that will work fine without any issues and send pic / location of the phone when he enters a wrong passcode or some sort of constant tracking or something.

3 I am aware about the find my iPhone feature and it works as expected.