Ouch tough situation
A couple thoughts. I have an 05 HSE (45 k on it) and have had both the parking brake issue (locking up on highway vibration) and the a pillar, sunroof tube leak. All is well now all is fixed.
For my parking brake, under warranty the dealer replaced the entire brake actuator / cable assembly and at 0.0 cost to me, did both rotors and pads as well. That was actually when the car was under CPO, not factory, warranty. It was 1 month outside of the 48 months when they did that, 0.0 complaints.
The root cause (other than faults with the actuator) is the shoes out of adjustment... dragging slightly, heat up, expand, drag worse and wala. Mine hasnt' done it since the new actuator BUT the brake has squealed / frozen when sitting still, but always fixed itself after key cycling / turning truck on and off.
I figured out how to adjust the parking brake, although I need a real torque wrench. It's a pain but saves me a trip to the dealer. Did it last weekend and my squealing/noisy parking brake is totally fixed. We'll see tho I guess. I agree, I hate the EPB.
As for a pillar leak. This shouldnt recur. There is a fix, you get a kit, remove the a pillar, use a black sticker to cover a hole in the body, break the "tab" off the a pillar molding that located the molding in that body hole, and use new clips to affix the a pillar molding to the truck. Do it on both sides, there will be no more leaks. Early RRSports had this issue also.
It could be your windshield cowl leaking thru the pollen filter OR sunroof drain tubes. I'd suspect both. Do a search here and elsewhere and you'll see how to fix or how to tell the dealer what's up.
Overall, sorry to hear about this, these are all solvable (EPB sort of) ... but can really make owning an LR3 a pain. I'm a guy who takes things apart, used to be a car mechanic looong ago, so I do alot myself, but for others, it sucks to rely on the dealer. Just be as educated as you can be and go in with all the ammo! Keep us posted !