It's not clear from your writeup, so I'll mention it anyway. After the fork, even if you set InactiveDestroy, it's important that the child not use the database handle. Basically, after setting InactiveDestroy, you should then destroy it. I wrote about this in DBI, fork, and clone..

As to your question, my reading of the documentation is that the array itself should not be modified. That is, you should not try to add a handle to it or splice one out or anything. What you're doing should be fine.