A:AnswerYes you can download all of those apps on this tablet, and I don’t see Serbian as a language option, but it does have other Languages in the same language family if that works.
A:AnswerToo general a question to definitively answer, but generally speaking, all modern tablets and smartphones are capable of IM and of running the Facebook app. However, this device is not capable of mobile/cell connectivity, so there is not way to switch service from a cellphone to it. Consult Verizon for compatible devices (as is true of cellphones, you don't have to buy the device from them, but only Verizon can tell you if your device is compatible.
A:AnswerYes it does have slot for use with a scan disc. It does not matter how much your scan disc can hold. Once you put the scan disc into the slot your tablet will recognize it and register it under settings. Go to settings to set up the scan disc to be used for backing up all files.