Hey! So here what i know from my understanding
1. I'm not too sure how many get an in person interview, but I think not everyone who got a 1st interview will get a 2nd one. Also, the program at Davis accepts about 20 ppl for the post bacc.
2. UCD will still be handing out interviews so even if your friend didn't get one there is still time! I think they do interviews all month of march and april.
3. Im on the same boat as you, I submitted my app on 2/26 and haven't heard from them, but that does not mean we can't get an interview. UCI also interviews until about April so there's still hope!