PCF fonts should go into misc/ not bitmap/, I can install the fonts on that website without going through any special configuration. I only drop the files into the correct folder. Let's go step by step:
Get the font:
mkdir -p ~/.local/share/fonts/misc
cd ~/.local/share/fonts/misc
wget -O pro.zip http://tobiasjung.name/downloadfile.php?file=profont-x11.zip
Place the font files directly under ~/.local/share/fonts/misc, and, as an extra zip them to save space.
unzip pro.zip
mv profont-x11/P*.pcf .
for f in *.pcf; do gzip "$f"; done
Force a cache update (just like you are doing), and we have the fonts:
$ fc-cache -f
$ fc-match -a pro | grep Pro
ProFont_r400-12.pcf.gz: "ProFont" "Regular"
ProFont_r400-11.pcf.gz: "ProFont" "Regular"
ProFont_r400-15.pcf.gz: "ProFont" "Regular"
ProFont_r400-10.pcf.gz: "ProFont" "Regular"
ProFont_r400-17.pcf.gz: "ProFont" "Regular"
ProFont_r400-22.pcf.gz: "ProFont" "Regular"
ProFont_r400-29.pcf.gz: "ProFont" "Regular"
If you use the fontconfig defaults there is no need to tweak fonts.conf or edit the font path.
Notes:
I'm using the local fontconfig path (~/.local, i.e. per user), per system path would be simply /usr/share/fonts/misc/.
If you really want to use bitmap/ instead of misc/ you do need the xset call.