You can turn off data usage in the settings, and you can also notify the carrier to have it turned off as well.
no.
It has Bluetooth.
Some of the notable differences are form factor sizes (Skyrocket is a touch wider, taller, thicker, and heavier), screen sizes (4.3 inches vs. 4.5 inches for the Skyrocket), HSPA+ (S2) vs. LTE (S2 Skyrocket), larger battery (Skyrocket), processor (1.2 GHz vs. 1.5GHz for the Skyrocket), internal memory (S2 comes in 16 or 32 gb versions, Skyrocket only has 16 gb...both have similar external SD capacity).
The Android OS on the Samsung Galaxy S2 Skyrocket is upgradable to Android 4.1 OS (Jelly Bean) in stock form, but could be upgraded to Android 4.4 (KitKat) if it is unlocked and rooted.
No, you can disable data usage in Settings (on/off switch), or you can also set data limits if you're on a tiered plan.
iPhone 4s
The Internet Galaxy was created in 2001.
It has, and it recently upgraded again to Jelly Bean (4.1.2).
It came out November 2011. AT&T was the exclusive retailer for it, and was the first LTE phone they offered.
The ISBN of The Internet Galaxy is 0-19-925577-6.
As the Samsung Galaxy S2 has reached its service life, which typically for most smartphones is 2 years, it is not expected to receive a OS update from Samsung or the carrier (AT&T in this case). However, there are a number of custom ROM's that are KitKat to choose from.
It does not appear to be available, if it was even available at all. With newer phones (even from Samsung alone) flooding the market, it doesn't make sense to still offer a case for the Skyrocket, which is going on nearly 2 years old from it's November 2011 debut.