There's a terminal emulator ready for you to use, just search this board. I'm not sure what you want with that serial port emulation, since all you want to do is perfectly fine with running in userspace (reading input events, writing to the framebuffer). See e.g. Luigi's terminal application:
https://www.mobileread.com/forums/sho...d.php?t=109472 - but I think there were others featured in this board. Check out the Index (sticky thread).
As for not running the Java framework - that is probably possible, have a look out for what's starting /etc/init.d/framework.
Oh, and make a backup (using k3flasher or similar) before locking you out. Just sayin'.