SQL Server 2012 Developer edition questions
1: yes

2: yes. Limits generally are documented in the documentation. In this particular case you shall look to http://technet.microsoft.com/en-us/library/ms143432.aspx for all capacity specifcations for all editions of sql server.

3: Why you have to? Normally developers have MSDN (Microsoft Developers NEtwok) and get the licenses there.

Then - ever heard of google? Finsind a shop is trivial.

For example google and "sql server developer edition price" led me to
http://www.amazon.com/SQL-Server-Developer-Edition-2012/dp/B007RFXQAM


  so the only option seems to be, to rip the CD/DVD and then upload it to the 
  development server which would be a tedious process.


No need to "rip" - a file copy is good enough. SQL Server does nothing fancy with the install media. But generally I keep ISO files around for all the stuff I need to develop - easier than looking for the DVD anyway every time I need to install it.

Generally if you want to do anything professional - or even semi professional - these days better stop assuming copying an ISO file up to the cloud is tendious. You will move a lot more around than you ever think of. This is 2013.

If you would have MSDN you could just download the ISO from the MS official repositories.