With the raise of several mobile network technologies, load testing a mobile application has become a different ball game in comparison with normal web app load testing. This is because of the differences in the response times that occur in different mobile networks such as 2G, 3G, 4G, etc. Additionally the client being a mobile device has plenty of physical constraints such as limited CPU, RAM, internal storage etc. All of these need to be considered while conducting performance testing of a mobile application if one wants to simulate a scenario close to a real time condition.
Coming to your 2 questions,
1) Yes it is possible but the amount of manual effort that needs to be invested to make the script execution ready might vary (since you are mentioning there is data in encrypted format - some are easy to understand and some are just crude and difficult to handle using JMeter). But there might not be any app server setting that would be required to change (unless of course you are unable to handle the encryption with JMeter in which case, the encryption might have to be disabled for QA phase)
2) As rightly said by James Pulley, these values can be parameterized. However, I fear that these values will be validated by the app server and hence the values need to be appropriately fed in the requests.
You can refer to this link for reference on how to do Mobile Performance Testing for Native application http://www.neotys.com/documents/doc/neoload/latest/en/html/#4234.htm#o4237
.The same could be extrapolated to JMeter to an extent.