It's stated on the product support page that you cannot connect the phone directly to the computer using a USB connection because the 91-handset assistant does not support this model because there are no built-in drivers of the phone to be recognized. As Android has Linux as its base system, you can download APK package files straight to your SD card and then use the MyFiles to install the application.
Regarding the compatibility of applications, it remains at your choice to test applications unless the developer specifies that their application is compatible with your phone, then only thing to do is to try and see if it works.