I can tell you from past experience you will need to split the fry up because the cardinals WILL eat the clownfish fry. I had to put some together for a few days because I wasn't ready when the cardinal spit out the young. After the second day almost half (about 50) of the clown fry were gone.
A male Cardinal broods the larvae in this mouth, ( as you probably already know) once he disperses them they are up for grabs to any hungry invert or coral, some can and do survive.
You can not really raise the larvae of clowns in a community tank, their nutritional needs can not be met. I have seen it done with netting but it's difficult. Again, open season for hungry fish and inverts.
Yeah I was just wondering if there are clowns already laying in a tank and you add banghai cardinals...would the cardinals have a problem with wanting to breed because the clowns already are or vice versa