Although I'm sure people here are happy to share their experiences, what you say is true - it varies. No two people have the same experience with a boot model and a lot of us as adults who will wear a well-fitting boot for far longer than any growing child really have very little to offer in terms of direct experience re: a young skater's boot and fit for a young, growing foot.
Just because I, at my advanced age, might like my Jacksons (and I do) and am tortured in Riedells means nothing vis-a-vis the best fit for your daughter; the lasts for adult boots have very little to do with the lasts for smaller boots. Every boot has fans and detractors as the previous thread about Edea demonstrates very well.
I know you're trying to find the boot that is right (currently since her foot is always changing) for her foot, her skating level (stiffness) and her fit preferences (I like extra room across the broadest part of my foot and a vice-tight heel but that's me). Trying and trying and trying is, as I am sure you already know, the only way. It's time and $$$ consuming - and I know you know more about those aspects of it than I do!
That said, having her boots heat molded again risks very little and you might avoid buying a new pair right now. There's no reason that I know not to try that. If it doesn't work, it doesn't work.
Here is one piece of advice I would give if it helps. Kids are usually not quite as expressive and specific as adults about how boots feel when they try them on. They feel it; they may not express the fit issues in ways that would assist us. I am thinking specifically about an interaction I sat through at Skaters Landing not long ago while I was waiting through a sharpening. 9 year old skater getting news boots with terrific Dad as sidekick. She tries them on, they are laced properly by the fitter. When asked she says "they fit okay" and was non-commital beyond that. The Dad, who clearly knew his daughter, asked very specific questions (which the fitter picked up on and went with) - "how does your little toe feel on that side? on the other side? the same? can you wiggle it?" and so on through the whole boot ("is there any extra room there? or there?"). Results, the boot was a little loose in the heel and a touch wide - all things she never might have said. They went to another brand. It was a great lesson in kid communications - I was impressed!