Ethan yes they are 2 pronged and stiff to get out. I have just changed mine and I had to get a screwdriver between the plates to prise it out!
As for the headlight units I couldn't have done it without this guide although I was about to give up when the first one just wouldn't budge until I found that after releasing the 2 clear tabs if you twist the bottom of the light that runs along the bumper out towards you and pull up at the same time it frees quite easily and the other one then came out without all the swearing.
Someone mentioned that you can changed the dipped without removing the headlights by taking off the dustcap and I thought that when I looked but I still wanted to have a go. At the end of the day the design is a disgrace and these bulbs should just slide in from above cartridge style. And to think some countries require this to be a roadside job with spare bulbs carried in the car!
Also when I put my lights back in they all screwed in OK but I noticed a large gap between the light and the bumper so obviously they were not sat right in the white clip so I undid the screws again and did lots of pushing and shoving and they went OK. So make sure you check the alignment of the unit along the bumper by crouching down although a small gap towards the front is normal due to the weight of the bumper pulling it down.