My games have evolved into one BIG Game and it has over 700 sims in it. I made most of them. The others are either born in game or a few townies I've picked up along the way.
I use a spreadsheet and have them all listed. Names, addresses, if they were originally a townie or not. If they were born in game I show who their parents were. I have lots of other info too, such as age or days to aging up and level of their skills I know they've got. Some sims have all of this detail and some have bits missing. Townies I hardly played have lots of missing info.
I also record how they are related to my 'founder' sim, Patience and each of her ex partners. Most of the sims in the currently 13 worlds in the game have no relationship to any of them. But I intend to continue this through the generations as I play the game. I think Patience has at least 1 great grandchild so far.
So I know how you feel about having something disastrous happening. While I was playing the other day the game threw me to another house. I have a single male witch in that house. I have only played him briefly a few years ago. He's really only there to be a prospective husband to any suitable and unattached sim who may require a husband at some stage. He was on fire. I panicked as I don't want to lose him. I made him about 3 years ago and haven't played him for at least 2 years but he's in the world and I don't want him to be lost to it. I thought fast and in the end all I could think of was to use Master Controller to reset him. That worked. I went back to my active household and I got thrown to him again and he was on fire again - so I reset him again.
I'm glad you managed to find a satisfactory solution to the meteor issue.