Holes in brick mortar?
Holes near the bottom of the wall are &quot;weep&quot; holes that let any water that gets behind the bricks drain out.  These, however, are not weep holes and look like they were drilled to mount something to the wall.  Perhaps a hose rack or reel?
In any case, yes you can fill them in.  They are small enough that you could use some mortal-colored caulk.
By the way, you should probably address that crack also.