All that can happen is the regular powder may foam more, and that can spill out of the washer and makes a mess on the floor. If that didn't happen, then no harm done.

Won't hurt the washer. Add some fabric softener to kill some of the suds.

No, it won't be a problem. It might make too much suds, but not unless she used too much. Because there is less water, you need much less detergent.

the machine cannot feel the pain so it will definitely NOT hurt it. neither would it damage it anyhow.

it seriously seems that your daughter is smarter than you.