Can anyone tell me why memory phone is shown as a card and not as phone and why is named 0?
Also, I can't connect phone to usb because because something is going on with phone tethering or idk.. Is there any way to fix that?
For your first question, I don't really know the exact truth, but somewhat in 4.3 Sony changes the emulation directory, resulting in a newer location of those two storages.
Now, internal storage can be explored with:
/storage/emulated/0/
And external:
/storage/removable/sdcard1
Maybe because of such emulation, ES File Explorer unable to show the old "sdcard0" label because as far I can remember the old emulation directory was named "sdcard0" and not 0. Plus it was in /storage's root.
Your second question, I cannot help you with that as there are not many infos you are trying to expose. How about starting your phone on a safe mode by holding power button then long tap the power off selection on screen. Then you will be prompted about rebooting to safe mode. Tap OK.
After reboot, try connecting your phone with USB again