New owner with problems

[ASUMTNEER]

Hello all. I am new to the X5, but not new to BMW. I've owned several E46's and a couple E90's. I love BMW's even though I know they have their issues. I do most repair work myself, and enjoy doing it, but sometimes these cars worry me to death. I just bought a 2005 BMW X5 3.0L. It's got 105k on it and pretty clean. I inherited a couple of issue with it I will highlight below:

1- Hood struts are worn out (no big deal, I can fix that easily)
2- Hood release doesn't really work well. If you pull the lever inside the car it will release the hood, but the lever at the grill will not stay out for me to access. I have to wedge something between the hood release inside the car and the plastic so that it will not retreat back into it's original position. Is this a bad release cable?
3- Needs new brake pads, easy enough. Do I have to replace the pad wear sensors, or replace only if I break them.
4- Battery won't stay charged. New battery as of a couple of months ago according to the seller. I jumped it off the other day and drove it for a good 30 minutes. Parked it and it would not start 24 hours later. I'll have to do some more work on this to try and track down the issue.

Any help or insight would be appreciated. I have searched and come up with some ideas, but would like some "live" feedback. I really like the car and hope I can get it up to par so I can really enjoy it.