My PPL instructor told me a passenger brief is essential, but the emergency brief is good practice for when undertaking the CPL skill test where it is required. I think if you do do an emergency brief it's important to be sure about what you are going to do and make it clear that it is YOU that will do it. "I will rotate at.... I will land back on the runway..." etc.
My skill test was just over 2 hours. It's best to exaggerate your checks to make sure the examiner knows you have done them. I'm not sure it should be considered more professional to do the checks silently, I think pilot activity where passengers don't know what you are doing is when they start to become apprehensive or afraid.
In terms of emergencies, you'll definitely get the PFL, and be prepared for an EFATO when climbing away straight after it. Otherwise you can look forward to it in the circuits.
I'd ask the examiner to do the circuits last. It'll save you some money if it all goes wrong in the Nav.
For the Nav section, plan well away from any potential problem sites as the first leg is all dead reckoning. When you get the diversion, plan it, fly it, and while enroute sort out a position fix. That way you'll have all the time you need to sort it out rather than it being dropped on you.
The CAA charged me an extra £4.25 to send my license and log book etc. back to me. It did take around 3 weeks (Arrived yesterday).
Hope this helps, good luck.