Strategies for dealing with disasters

Citizens need a source of food and warmth to survive. Since the Help Menu states that citzens will only visit the nearest storage barn to collect resource then you can't depend on citizens going to your primary settlement to get resources. Even if they do take the long walk back to your primary settlement they will be wasting a lot of time doing so.

Your best bet would be set-up a Market near the offshoot settlement to ensure all the goods the citizens need are close by. Market Vendors will gather resources from Storage Barns and Stockpiles all over the map, so it'll ensure that citizens will always have the resources they require near by. The long travel time between the Market and your primary settlement could still cause some problems though, so you may need to put several vendors in the Market to ensure the Market always has a sufficent number of supplies.

Another option would be to build a gatheres hut, forester and woodcutter. The gathers hut combined with the foreseter replanting trees should ensure they have enough food. The woodcutter and logs provided by the forester should ensure they have enough fuel to keep warm. I suspet they won't have access to clothes with this method, but that will just decrease their productivity. So long as their homes are warm they won't die they should just work less and spend more time indoors where it's warm.

You only need 1 animal to breed them, technically. However, animals can die off for no particular reason, which means that you are best off buying at least 2 since the livestock trader is so rare that you don't want to risk having one die off immediately and having to wait for the next trader. Animal birth rates depend on if the pen is worked and how many animals are in the pen (more animals means more babies)