1. Can you change the name of the hobby lots? They have failure names, simply put. But I'm not sure just changing them on the lot themselves would suffice since they're referenced in memories- therefore, can that text memory string be altered? Safely?
You could, but I imagine it would involve more extensive work that you are capable of performing.
2. Is there an approved awesome method to modify the Hobby lots, terrain, names, neighbourhood, etc?
Nope. Pretty much any attempt to do so involves a great deal of arcane chicanery in SimPE. And if how to do this isn't apparent to you, it's probably not something you can do. It CAN be done, but not in any way I would recommend to others. Professional: Do Not Imitate.
3. Not quite 'Oops, I broke it!' because I'm not sure I did break it yet- In my test hood, a guy brought the Repo Man home from work. I nixed all relationship he had to the guy and it hasn't happened since- but why might this have happened? Is it a VBT? How do I fix that?
I think this is a naturally occurring game bug.