So, after following the instructions on the driver's manual and other sources like the LBP3100 thread on this forum, Ubuntu's wiki, Arch's wiki, etc... the printer still didn't print. The problem lies with /dev/usb/lp0 not being created, which is weird because Mageia 4 doesn't blacklist usblp like othes.
After a bit of digging dmesg's messages i noticed that lp0 is in fact briefly created, but destroyed right away for lack of proper driver detection. A bit of searching led me to https://bugzilla.redhat.com/show_bug.cgi?id=873123 an luckily that solved my problem.
Long story short: after you've added your printer like stated in the driver's manual, you must execute this 2 commands:
lpadmin -p <printer> -R usb-unidir-default
lpadmin -p <printer> -o usb-no-reattach-default=true
Maybe this should be on the wiki somewhere to better help other users?