Sims 4 Crashing at Random Intervals

whiletheflies​  The lastcrash files are mostly unusable to anyone outside Maxis.  We (volunteers) do ask for them when we hear that someone wants them for a specific issue, like when the SimsDirect account posts an info request in one place, we try to ask anyone we see with that issue.  But I don't think they're looking for lastcrashes for Innisgreen issues right now.  They are looking for saves though, in this thread:

[PC/MAC] [EBN] Frequent crashes in Innisgreen | EA Forums - 12369004

That is specifically for a crash in that world, and reproducible with no mods or custom content.  If you want to share a save, EA_Solaire asked for them in this reply:

[PC/MAC] [EBN] Frequent crashes in Innisgreen | EA Forums - 12369004

You could include your lastcrash as well; worst case, they don't need it and don't read it.

One other fairy-related issue I'd read but had forgotten is when the fairy has different skin tones in their two forms.  So if yours do, switch them to the same skin tone and see whether it helps.