Thank you for the update and photos.
There was a lot of fat wasn't there. Not sure about the oviduct, hopefully someone like @coach723 or @Eggcessive will chime in.
I see. Yes, does sound iffy in the fridge. Freezing may cause some discoloration and make it harder to determine the cause, but it beats not doing it all.
I'm so sorry about Idgy:hugs
It's good that you will investigate further. It's better to refrigerate the body instead of freezing it. Are you going to do your own or send/take the body to your state lab?
A link to your state lab system.
https://cahfs.vetmed.ucdavis.edu/
Sadly, reproductive disorders are common.
It can seem a bit odd if you have more than one get sick or lose them in a fairly short period of time. Reproductive problems can strike at any age and any time, it's frustrating for sure. I you happen to lose this sweet girl, you may want to...
Can you feel inside her vent for an egg just to make sure there's not one stuck?
If she's lethargic, I would not soak her, place her somewhere quiet and relatively warm.
Sometimes hens with reproductive problems can temporarily become lame/not stand due to a mass pressing on the sciatic...
Photos of the poop would be helpful.
You mention her crop was about the same this morning as it was last night, so it did not empty completely correct?
She also stopped laying when you noticed symptoms, maybe a little before that.
I would try to get her hydrated. Direct drench with the Corid...