HT, Atmos, 4K questions and more

Hi

I have a number of questions please. My HT that I am building is taking shape. It is not perfect but I think it is going to be lekker when done.
Some questions that I have are:
- I'm assuming any BluRay player can output Atmos? I have a very cheap Samsung unit.
- Where is the best place to buy Atmos disks? I have checked on Takealot but the disc description does not seem to indicate the sound formats.
- I see 4K discs are getting more plentiful. If I have a normal 1080p Optoma projector, will it still display a picture if a 4K disc is played on a 4K player i.e. will the player or AVR downscale the image?
- Are there any affordable region free 4k BluRay players in SA? (A quick Google search brough this up http://www.ultrasound.co.za/pioneer-bdp-180-bluray-player)
- What media player supports Atmos? (I'm assuming "standard" ones such as the Mede8er etc do not)

I downloaded a few of the Atmos clips (leaves falling etc) and stuck it on a memory stick and plugged that into the Samsung cheapie. Sound output is set to bitstream. I see the pictures but get no sound.  :sd:

Appreciate the expertise shared ....