Can an iPad be a stand alone device separated from iPhone and or computer?

Yes, absolutely. You do not need a Mac or iPhone to use an iPad. An iPad is a computer in and of itself.

Yes. There is no requirement to own either an iPhone or a computer in order to use an iPad.

Also, if you don't own a computer it seems likely that you may not have wi-fi. If that is the case, you may want to consider whether to get a "Wi-Fi + Cellular" iPad or a "Wi-Fi" iPad. See the Connectivity section of the following example: Buy iPad 10.2-inch - Apple

If you don't get the Cellular version and don't have wi-fi, then you would want to consider having wi-fi installed in your home if that is where you intend to use the iPad.

Yep.