Alextp, if you used this
https://wiki.freepascal.org/Cross_Compile_to_RasPi_from_Linux to setup your cross compiler, I did not test for or even cover Qt5, its all GTK2, sorry !
But if you look back over the process again, we grabbed a whole lot of libraries from the RasPi and took them over for our cross compile setup. If you have already setup your RasPi for Qt5 apps, you will get libqt5pas1 with the rest. Or should.
So, please go back to where you got the arm libraries from, see if they include libqt5pas1, sure you can work it out from there.
libqt5pas-dev is equally easily fixed, all i really contains is a symlink
libQt5Pas.so -> libQt5Pas.so.1.2.8
You may need to make that symlink in the directory where the arm libQt5Pas.so.1.2.8 library is on the cross compile machine.
Untested but should all work ...
Davo