It is possible, but it would a webcam app (ie: SimpleWebcamApp is one out there, available outside of Google Play however), terminal app/Terminal Emulator, a webcam that that has low-to-moderate power usage, and a USB OTG cable.
If you mean the ability to video chat, yes. You can use Google Hangouts, Skype, etc. to activate the front camera on your tablet.
Yes, you need to have a working Google account to use this tablet.
no
Yes, you can use multiple Google accounts.
the nexus one can use 802.11b and g and it is capable of using n but google have yet to activate it it seems the hardware is there for it
Yes, it is available in the Google Play store.
Yes, you can use the Nook app, which is available on Google Play.
On the surface, it may not appear that you can make calls on a Nexus 7. However, you can do so if you use VoIP software (Voice over IP) such as Google Voice.
The Nexus 5 in either the North American or International variant should have enough network band options to be usable in Dubai. See Related Links for the bands it supports.
Nexus phones use Android OS. Unlike most Android phones, the Nexus line are considered "pure Google" phones as the OS does not have either manufacturer and/or carrier modifications (in the form of "skins" and proprietary apps). They also typically receive software updates ahead of carrier phones.
Sprint's Samsung Nexus S 4G is the first of the Nexus phones with 4G capabilities, and it builds nicely on Google's legacy. The phone features top-notch Samsung construction with the streamlined user interface of stock Android. With Android 2.3, 16 GB of internal memory and a 1 GHz Hummingbird processor, the Nexus S 4G is a powerhouse of a phone, allowing for true multitasking and enjoyment of multimedia. Of course, since it's an Android phone, it integrates seamlessly with GMail and Google Calendar, but Sprint has gone a step further, offering seamless integration with Google Voice as well. All the Google services you use to organize your life and stay in touch with colleagues and loved ones will be always at your fingertips with the Samsung Nexus 4S.
The Nexus One was Google's first foray into having their own Android-powered device. The phone was aimed for app developers and tech enthusiasts, and were the first to get OS updates ahead of anyone else. The hardware was at times ahead of its time, and years later, can still be seen in use.