I know this has been covered in other places, but I've been getting conflicting information on how safe different methods of changing names are. From what I've read, changing a sim's first name in SimPE is generally unsafe, and it's recommended to use in-game tools like the Sim Blender or Lot Debugger. What's confusing me is how to approach last names. Some places say it's safe to change them with in-game tools by copying a first name to the last name, but The Sims Wiki advises against changing last names in-game because it may not update all references properly. I'd just like some clarification on this.

It's fine to change last names in SimPE, and I've never heard there to be any problem changing them in-game, either. It's also pretty much fine to change first names in SimPE, the only thing is that if there's an error that occurs during that sim's interaction the error log will display their old name from before you changed it. I think that's pretty much the only difference.

I think the reason their old name still shows up in the error log is because changing their first name in SimPE only changes the name in their catalog description, not their object data. I think those in-game tools change all of it, don't they? I guess I just wanted to know why the wiki said changing last names in-game could cause problems.

Yes, the in-game tools use the name baby dialog, which changes everything.

Last question: Could I just erase a last name by leaving it blank, like what all the stray pets have? Would that cause any issues, and would it matter if I use SimPE or in-game tools?