The room at Fosdem looks ok for me, even if it is not so… let’s say comfortable
I could maybe propose an equipped room in the cultural center where I work, but is quite excentred. It is located in Forest, but well deserved by public transport, not far from the Midi station : Le Brass - Centre Culturel de Forest
Avenue Van Volxem 364, 1190 Forest
02 332 40 24
Regarding the restaurant I would go to Chaussée de Boondael, there are plenty of never-closed-bars frequented by hordes of students and I know at least one good restaurant that can probably host 20 people : La Mirabelle
https://goo.gl/maps/SV49ByLrraP2. Would you like me to take contact ?