Your daughter sounds like mine Muppet. She'll be 8 at the end of the month and if it weren't for the length she could still wear a 3 or 4T lol. Totally have to love having a cool down rider! Mine does that for me quite often. She's been on every horse I've got aside from my yearling filly and if it were up to her, she'd have been on that one too.
A crop can be a helpful tool with little ones too (if they are confident enough to 'spank' a horse anyway). My old WP mare is one that will test, big time. Go to the gate, stop and refuse to move, etc. (She's the typical older lesson horse these days) Gave DD a crop, she gets a spanking once and since then she hasn't given her even the tiniest bit of grief.
ETA - Foxhunter, I've met my share that are/were like that too. It's funny how they differentiate who is on their back. Smrobs also has one that is the same, Buck (I think?) that was deemed a killer and quite the handful for an adult but is a great babysitter.