Do you have boy/girl twins by any chance, @Alalalalalongalalalalalonglonglilong ?
It’s natural to think through the “what-ifs” when auditioning, but do be realistic about the chances of success.
There are two ways to audition for a production. A casting director can invite a child to audition, usually after their agent has submitted the child for an advertised role via the casting platform Spotlight. In theory, the odds of success are slightly higher in these circumstances as a casting director looks at the submissions and then selects only the children that are the best fit for their idea of the role to audition.
The other route is to audition via an open call, where anyone is free to apply. Because there is usually a wider pool of applicants, the odds of success from an open call are usually much smaller. I’m pretty cynical after 9 years parenting a young actor, and in my experience the majority of open calls are a box-ticking exercise that casting directors carry out just in case there is an unexpected “perfect fit” out there, or as a last resort when struggling to fill an unusual or very specific brief. Open calls are usually conducted in parallel with invited auditions for experienced children from top agencies, and it is far more common for one of these children to book the role than a complete unknown - unfortunately that’s just the way the industry works.
I had the impression from your OP that this audition might have been from an open call, in which case I’d suggest you all enjoy the experience of filming the tape and then forget about it. You don’t usually get a “No thanks” from a first-round tape, just radio silence.
If your DC do get called back, there will be plenty of time to make decisions further down the line. For key roles in a feature film there would normally be recalls, director’s meetings and often a chemistry read or screen test before an offer is made. That process takes weeks rather than days, and you can choose to pull out at any point if you feel it isn’t going to be workable.