>>3This is how I personally would deal with them, however I do not not if it is the 'right' or 'ideal' solution if there is such a thing.
Give it some time, every person is different like I said so I'd take the time to get to know them, see the reasons behind their actions and gradually ask about it accordingly to said persons.
And, I do believe you're already on the right track, sincere happiness and smiling is infectious so it may or may not affect them.
However, each to their own. For now, go along with it and see how things go, if something happens you can bump this thread back and update what's happened and ask for advice then.