Id like to now how to make bspwm open those terminal applications in floating mode.
Create some rules in the ~/.config/bspwmrc file.
from the example on git:
bspc rule -a Gimp desktop='^8' state=floating follow=on bspc rule -a Chromium desktop='^2' bspc rule -a mplayer2 state=floating
To get just those applications to float, but not st itself, may require some scripting. I don’t know if the bspwm rules can be set up so that something like:
st -e cmus
will float; maybe try by naming the terminal as well. Worth a look at the main bspwm thread on the Arch forum to see if this has been done.