I recommend instead of rain pants considering the Zpacks CloudKilt. I just received mine, so no real user review yet but I think it'd suit nicely. It has a cinch cord in the front so you can cinch it nicely around your waist, and you can unzip the back as much as you need to open it up and give you space for a good stride. It'll keep your thighs nice and warm, while being exceptionally light and still breathable. It rolls up smaller than my fist and at 2oz hardly adds much weight to your gear. If you talk to the guys over at Zpacks they might even be able to make one that defaults to a larger stride for you.
You also might choose instead to try the Patagonia Houdini Pants, which are windshell pants and very lightweight. At 3oz they don't take up much space either, but are merely water-resistant. I find that they add quite a bit of warmth!
For a hard shell, I'm thinking you might try the Marmot Super Mica or one of Outdoor Research's TorsoFlo jackets. The cool thing about the TorsoFlo pit zips is that they extend all the way to the bottom of the jacket, making it essentially a poncho if more ventilation is required. Another choice might be the Arcteryx Alpha SL Pullover, which has one enormous pit zip on one side (down to the hip) and one regular-sized (but also fairly deep) one. The large zip is used to make it easier to pull on the jacket, but is also easily abused to add ventilation. There is a snap at the bottom to keep it from flapping around.
I was originally thinking about the Patagonia M10 for you but it lacks pit zips, a pity since it is so light and packable.
For the headlamp, I'm a huge, huge fan of the Petzl Nao. It automatically adjusts between a floody beam for near and a throwy beam for far depending on the lighting conditions and your needs, and you can program it using your computer to set it exactly how you want it. It'll illuminate up to 350 lumens and it is very easy and fast to swap out the battery pack for a spare. Petzl claims it should average about 8 hours of run time on its default Level 2 setting (up to 100 lumens), which is pretty good. The reactive lighting sounds like a gimmick at first, but after using it extensively on a few trips I wouldn't take any other headlamp.
The other headlamp you could consider is the Zebralight H600, which will also create an impressive amount of light and is certainly a cheaper option. However, I find the automatic adjustment feature on the Nao to be absolutely worth it as it is hassle-free and ideal for both looking off in the distance and looking towards your feet.