Adding break dancers, human statues, social workers, witch doctors, and any other NPC without a real name will corrupt your hood. Fortunately, if you didn't touch the universal NPCs, your installation should be safe and you can just start a new hood with no corruption.

It is not safe to have children by the Grim Reaper if the way you get those children is via woohoo, since it is not safe to do any of the things that make the Grim Reaper able to be woohoo'd. I believe it is safe if you have children by the Grim Reaper using the Tombstone of Life & Death. However, all you get are generic Face One (maybe Face Two) babies with pale skin, black hair, and blue eyes. They don't have any special features or powers or anything. I don't find it worth the bother, myself, but you might.

I using the inteen clock or L/D tombstone.
I use it sometimes for story purpose. "Forcing" a young maiden to bear his kids and the offspring will become "evil" sims (or grim ripper "servants" that kill off sims (with the simwardrobe hacked objects) that are annoying, boring or evil. Bwhaha! Similare to that serie killer Jack the Ripper from the 80's.

I'm not sure about the InTeen clock, but the Tombstone of Life & Death is (I'm pretty sure) a safe way to have babies with the Grim Reaper, and it sounds like it works for your storyline, so that's all good.

Just wanted to chime in that before I came across this site I created some rather huge corruption in my game by deleting things left and right and using cheats to get around the game before learning of custom content. When I learned what I was doing was breaking the game I stopped. Main stupid thing I did was deleting tombstones thinking "they're dead and it'll remove the file"; trust me it's not worth just letting the file sit on your computer and moving that tombstone to a graveyard lot or other location.

I've been playing that neighborhood for over 2 years now as it's where most of my most enjoyable Sims live. My only disaster so far was saving a lot at the wrong time which caused the game to crash when I loaded it and took it out of pause. I was lucky as I was able to save the family by moving them out and to a different lot, but to reiterate what everyone else has said just because the corruption isn't visible doesn't mean it isn't there.

My best advice: make sure to backup regularly. I use a zip file program and name the file "N### YY-MMDD.7z", where N### is the neighborhood folder and YY-MMDD is the year, month, and day of the backup. That way when the neighborhood does crash (I wrote about when I thought mine did once) I can try to find out if it's the entire neighborhood or just a particular file.

As far as the Grimm Reaper thing, instead of bothering with that might I suggest declaring a Sim in the neighborhood as "evil" and doing the Grim Reaper story line with it? That way it's just two regular Sims and an otherwise normal situation.

It'll be the same coding just activated on the clock. That's how nearly all of those functionalities are done.

Jaytee95 Personally, I dont find it bothering (nor hard) to do at all.
Im often using the Life and Death Tombstone regulary so Im used to this kind gameplay and that kind storyline where the mother is bearing a child from that guy. Little bit like the Specter story. (and creating the child in cas is a tad boring, I like it more random).

(and as for as tombstone and backing up, thats something Im already doing. The area where Im still at a beginner stage is preventin or fixing the game outside the game, like SimPe. I use many of the hacks suggested at many populare creators and the ones recomembed in the wiki posts to prevent somewhat game corruptions like the no link tombstone, no trash memory, lot debugger, the MATY no-townie/pet/professior mods. that sort kind of hacks ...though I still a bit unsure if the formers one do any favors to game in long run. )