The bold part is the sentence in question, the rest is for context:
The full text can be viewed here.
First, my attempt at translation:
"The longest time person shall be here for 15 years, but the shortest time person shall be here for 6 years."
1) Is は in
in a contrastive way here?
2) The positioning of でも is a bit unusual compared to what I've seen so far.
It seems almost like a suffix to 方, although it surely isn't. However, does this position have any consequence on its meaning? Does it become nuanced in a different way?
3) I still feel a bit uncomfortable translating "一番長い方" into "the person who has lived (here) the longest." I know there is very strong contextual support here, but it still feels like I'm adding too much xD So I just wanted to know if this is a common way to express this? Or do I have to be cautious in cases where the context isn't as strong as it is here?