do i have to point the oxce-folders to somewhere else?
they are all pointed to /openxcom/
This is the most correct option settings. All game data is located in the same openxcom folder, in the internal memory of Android, to which the application has access to both read and write files. You can change these settings, but you need to understand what you are doing - there is a risk of failure.
and i can't choose xpiratez as a mod, only ufo & tftd
It’s hard to understand what could have gone wrong. If everything was done according to the instructions (and it looks like it was), then the absence of X-Piratez in the list along with UFO and TFTD can only be explained by the fact that the game was not restarted after moving the piratez folder to openxcom/mods/. OXCE should re-check this folder for mods, and this only happens at startup.
But this is only an assumption, maybe there was some other reason.