There was certainly a response from Milla regarding Olivia Jackson.
She's quoted from Facebook at Deadline.com
“I sit down to write this post with a heavy heart, because a terrible accident rocked our set on Saturday the 5th of September. My incredibly talented stunt double, Olivia Jackson, collided with a camera crane while performing a motorcycle stunt and it put her in the hospital with severe, multiple injuries. The cast and crew of Resident Evil: The Final Chapter have been totally devastated and are waiting with bated breath for news on her recovery – we now understand she is stable and being carefully monitored by very experienced South African doctors."
See link above for full statement.
and Collider via Gamespot.com
"We were going to pull the plug on production, period; it was close," she said. "What happened to Olivia was a nightmare, plain and simple. [Director Paul W.S. Anderson] was crying on the phone; I have never heard the man cry in the fifteen years that we have known each other, I mean it was the most shocking thing that I have ever been through, that Paul has ever been through and anyone on these movies has ever witnessed."
Again, full comments at the link
Ricardo Cornelius wasn't a stuntman but rather was a member of the production crew.
Given that his death (after being in a coma for some time) is somewhat more contentious than a stunt going wrong the apparent lack of comment may have more to do with liability issues than lack of sympathy.
Also at Gamespot
This accident did not happen during filming, which wrapped up on December 9. EW reports that an investigation into the accident may be ongoing.
"We are all deeply shocked and saddened by this tragic accident, which was out of anyone's control," a spokesperson for Constantin [Films the production company] said. "Our thoughts and prayers are with his family."