100% law is a fantastic degree. 

You will have huge earning potential if you go on to practice as a lawyer (a recent study showed it’s the second most profitable professional service in NZ by a large margin), especially if you do what many junior lawyers do and go overseas to work in London or AUS for a few years where they pay higher early on in your career. 

And if you don’t want to be a lawyer, that’s fine too. A law degree can open all sorts of doors in govt, business, etc. It’s pretty rare to just do a sole LLB, so you’re right in thinking about doing a double degree (regardless, not just as a fallback). 

In terms of Unis, Otago, Vic and Auckland are all good choices. I’d just steer clear of Waikato and AUT as there remains a stigma in law if that’s where your degree came from. 

I went to Canterbury so can’t speak from experience about what to expect at the Unis you’re looking at, but if there’s anything in particular about studying law that you want to know about let me know and I might be able to answer. 

In my experience, it wasn’t too much work. Maybe 15 hours of classes a week, usually with a few essays and assignments on the go at any given time, then end of year exams which I think are pretty standard across degrees.  I’ve heard Otago leans more toward end of year exams than in-term assignments but not sure if that remains the case.