Haven't noticed the brightness being turned down automatically but here is my take on your other issue-
Phone calling out automatically. Unfortunately this is a wide spread problem all phones seem to suffer to varying degree if their keypad and touch screens are exposed. The reason why is programmers made a decision to call the last nuimber in the history with a simple tap of the green call button and with touch screen also. There have been numerous solutions and even people selling software to fix the issue. Most don't work! What you can do is the following which I find is a 90% good solution-
Set the phone to shut off all buttons and touch screen when the phone is powered off. This will keep your phone from being triggered by accidental touching WHEN POWERED OFF. Unfortunately part of the cell phone service is that they turn your phone on when you receive a call. This can be a disaster if you receive a call from someone and then you bump the phone whiole in the holster and now that person can listen to everything you say. Worse yet, even if you don't bump before it times out and his call is now in the last number cue, you bump and your phone will call him back on its own. Verizon nor Sprint tech groups have no solution for this. One additional step to get around this is to set your phone to have a password everytime you call out and a password evertime you power back on. This is the best solution unless you also do unattented system backups. The PW will prevent you from executing an automatic backup. Not to mention the user inconvenience of dealing with passwords. I do backups so I can't use the PW protection from automatic call out. There is only one way we found that is a sure fire way to protect your security from auto call out and this is to put the phone in Flight mode and then power down and put in your holster. Inbound calls will go to Voice Mail and you won't know about them until you take your phone off of Flight mode. This is what I use here and since, I have not made calls to last number in the cue and I do not get calls auto answered when I'm not present. That works and for me, has less hassle than the passwords. Trust me, we've been in the war zone on this and it is not phone specific. I've had this issue with every phone that has exposed keys for the last 6 years. Some are just worse than others and those would be the PDA touch screen phones. But none seem to be exempt. Just last Wednesday, one of my clients I just spoke with , who uses a Mot Razor on T-Mobile that closes and protects the keypad, called me back about 30 minutes later and I heard him arguing with his girlfriend about her spending too much money on his credit card. Really funny but, dare I tell him what happened? Noooooo!
So you have options on how to deal with it but none are perfect.
Simple way to prevent the WMP from pausing while in the case-
WM5 allows you to open multiple tasks. Once I get WMP playing my playlist of sounds, I then launch something else that isn't affected greatly by the screen, take your pick, like new note. Now you can continue to listen as long as you have that option not to pause the sound when in another application and your pause button won't get tapped.