It is possible that shortly, my wife and I will have 2 non paying guests for a few weeks. ( until their house is ready to move into ).
Would we need to inform our house insurance company if they did move in ?
You need to check your policy. Most allow you to have friends over a weekend but not people staying longer periods. If in doubt, check with the insurance company and if they say you are allowed to do it get them to point out where that permission is in your policy.