Dear Loose Nut:
First of all, jolly good job that both you and your wife were not seriously injured in what was a very bad crash. Please don't be too hard on yourselves. Accidents can and do happen to everyone.
Lessons learnt? Plenty!
I've only flown a Gazelle once, over twenty years ago. I picked it up into a hover, then started a left pedal turn. The other pilot immediately over-rode me and told me to make the turn to the right. Although he did not have time to fully explain why, I now understand. And now that we're more educated as to the interaction between the main rotor and fenestron, we can all be better prepared to deal with the handling peculiarities of this model. It is noteworthy that Eurocopter has markedly changed the fenestron design on later models.
I have only one gentle observation to make, and hope you don't take offense. The accident report made reference to "witness marks" on the ground, made by your helicopter at its initial lift-off point. Many helo pilots are in the habit of allowing the ship to come off the ground with some yaw, assuming that they'll get it stabilised once airborne.
This accident reinforces why it's so important in the Gazelle to get the yaw-trim correct as the ship is light on the skids and before breaking ground. It is not easy, it takes real work, and is often a challenge for even us experienced, commercial pilots when the wind is at its most disadvantageous. So I do not fault your wife.
Again, don't beat yourselves up over this. I do hope that this accident has not put you two off of flying, nor off Gazelles. Wonderful ship!