I think the difference is the focus of the sentence. I'll give an example of what I mean:
The natural breakdown of this in speech would be like:
我住 - 这里
The focus is on the action of you living here.
Here, the natural breakdown of the sentence is like:
我 - 住在 - 这里
This breakdown is a bit different. The "you" is separated by the gaps in sentence from the action of living here. I think it puts greater emphasis on the "you".
To go back to the original question:
The important part of these sentences isn't the people themselves, new or old, but the fact that they live in a certain type of house. And so, I think it makes more sense to use 住 instead of 住在.