Well, I guess that might be interesting, lol. I'm so glad that things are working out well for your dd in the gym under the new HC though. Tell her not to expect much when seeing the old HC at meets, that way she won't be disappointed if old HC snubs/ignores (hopefully nothing worse than that) and she'll be pleasantly surprised if the old HC is friendly/supportive. I can't remember exactly how old your dd is, but I think she's probably old enough to prepare her for both ways.
We ran into my dds old coach twice last year at meets, and had the snub/ignore side of it. DD was confused as to why old coach was not being supportive, but she was only 9 and I brushed it off as "she's just very busy". She bought it, but I don't think she'll buy it this year if old coach is still of the same attitude. We'll cross that road when/if we come to it, but I think dd is wise to the ways of that coach now and won't be expecting a friendly hug, lol.
Good luck to your dd this season! Sounds like training under new HC will be a great thing for her and she'll have a great season.