Do the cameras need to be plugged into an outlet or do they run off battery power?
There is a power adapter included that is capable of powering all 4 cameras. The video/power cable included is plugged into the camera then pulled back to the receiver to plug inso you would put the power adapter close to the receiver. 

Can I mount the "Bullet" camera on the ceiling or it has to be on the wall?
You can mount these on the wall or ceiling.They are fully adjustable 

Do the security cameras capture audio and if sois the audio recorded?Do the cameras record sound?
Nope. They barely record images!!!The system has the ability to capture audio but that equipment is not included in this package deal.You would have to buy additional equipment and run additional cabling. 

What's the difference between the bullet & the dome cameras? Can the dome cameras be moved around remotely or will they follow motion?Can dome cameras be wall mountedor are they ceiling mount only?
The cameras can only be moved manually but they have a very wide angle lens. 

How are the dome cameras construction.Are they rain-tight weatherproof?
The cameras are sealed in aluminum housing according to mfr to IP66 level of ingress protection which means it can take a powerful blast of water from any direction without loss of function. These should be fine for direct rain exposure. 

How is the night vision? Clear or grainy? Is the night vision in color?
It is good.You can add some infrared LED spotlights on the area you want illuminated.It won't show bright to the naked eye but IT will be a crisp clear black and white image at night.No. Most night vision is not in color. 

Can the siamese cables be run outside the house? Are the cables weatherproof too?
Yes 

Does the power to the cameras and the video both go through the same wire set？
The cable has double wire with double ends.

Hello how are the cameras powered?
They are wired in.They come with everything needed

How and where does one get longer cables?
You can get them from Amazon

How long is the included cable? it doesnt say on the description anywhere?
4 at 100 ft. 

Will sound be available through these cameras?
No. 

What is the viewing angle? 
75 degree.

Does the security camera have capability to zoom in and out
It has the ability to do a digital zoom via the software. There is no mechanical zoom feature

Is there any way to turn the ir off?
Yes you can set the IR to Auto On or Off. 

I live in a cold climate. What temperature do these cameras operate at?
metal IP66 security camera are completely airtight against dust and able to endure any kind of wind and rain. Outdoor cameras are capable of operating in extreme temperatures -20°C to 60°C or - 40°F to 140°F.

What is 30 fps?
It stands for 30 frames per second.This determines how smooth the motion is in the video. The lower the frame rate the more staccato effect you'll get. 

Is there a functional difference between the dome and bullet cameras? Or do they just look different? I don't know which one to choose.
With bullet cameras the angle can be easily changed for example by someone accidentally hitting it with a ladder. Also someone could intentionally change the angle if they don't want to be video recorded. The domes prevent (or at least make more difficult) this type of angle-changing. If the camera is relatively low domes may be better. If the are high up bullets may be sufficient. 

Can dome cameras be wall mounted or are they ceiling mount only?
Either way.

Does each security cameras have to have its own power supply?
It comes with a splitter.Yes the 4 cameras system  have 2 power adapter one for DVR and other for Cameras The 4 cameras would be charged from 1 power supply via 1-4 splitter.