Her being special only extends to her Mental Shield, which she had as a human and had amplified when she got turned. Aside from that she didn't have any powers like heightened perception. She saw them moving several times without any real problems.
Riley on the other hand was in the dark, in a rain storm. You can even see him squinting several times(presumably against the rain).
Doesn't change the fact that Bella saw them, and Deadpool saw bullets in flight. Ed Windu isn't so fast that he can't be seen, especially not by Poolemort.