Belgians and the Battle of Hannut/ Gembloux

As far as I can tell some Belgian units formed a screen in front of the French Cavalry Corps of General Prioux on May 11th. They then seem to have moved to join other Belgian units on the line of the R. Gette by May 12th.
 
It is possible these were Chasseur Ardennais units moving from the Ardennes west to rejoin the main body of the Belgian Army.
 
My questions are:
　
1) Were any Belgian units involved directly in either the Battle of Hannut or the Battle of the Gembloux gap?
If so which units?
 
2) Did any Belgian units form a screen to give warning of a German advance and/or to delay any forward moves by German light e.g. reconnaissance, units as the French cavalry advanced into Belgium 
 
3) If any Belgian units did screen the French advance were they effective?
 
4) Was any link up expected between the French and the Belgians with regards to forming a defensive line in the Gembloux gap apart from the French tying in to the Namur Fortress?