It is possible to sync several iOS devices to the same computer account. I do it all the time with an iPhone and an iPad, it will also work with two iPads.
Nope, it won't work. Apple disabled the functionality a while ago with an iOS update. It only worked for few months on the first iPad with the Camera connection kit.
I tested it on my iPad 2. If I remember well, when connecting an Apple USB keyboard it poped a message that said the connector can't provide enough power ... Probably a fake reason because it worked before.
Best Answer
RAM is hardware within your iPad that is soldered in place. It can not be upgraded.
The amount of RAM depends on your model of iPad. Newer iPads generally have more RAM.
RAM is part of the system on a chip and not replaceable separately even if you disassemble iPad.