OH! A Sprint Tech told you....and that means....?
I'd still wait it out another day before changing ROMS.
Under the guise of "anything's possible" I'd say yes an app MAY cause issues just by installing it.
The true test is a little bit tedious and long but it's gotta be done somethimes.
Install the ROM. That's it, no kernels, no themes, no apps (a bit extreme I know) Run the ROM. How long is up to you but you need to verify that the ROM is running correctly on your device before making ANY changes.
After that add apps but only a few at a time, if you add twenty at once and things get wonky you cant know which one it was.
If you rule out your apps then go to the theme, etc, etc.
Well if you are running the encryption then you need to enter the SAME encryption key on your PC/laptop or it wont connect. You *should* be prompted for it but it all depends on your system.
I'd suggest changing it from abcdefghijklm