My family has had lots of awkward moments, visits, years, relationships, etc.
So, to me, reading your story, it sounds like your father may have been living with a "friend" and didn't want you to know, so he imposed on his other friends to take you in during your trip--which would put them in the awkward position of covering for him and being a bit dishonest with you.
Or maybe I've just got too wild of an imagination, have watched too many TV dramas, and have had too many unfaithful lovers myself.
Tangentially, for several years I've talked about getting a DNA test in case the eggs my daughter sold 20 years ago grew up to be someone who wants to find me. Recently that daughter told me about a friend who had had the test and learned that their father had unknowingly fathered a half-sibling during a one-night stand with an exchange student. That knowledge caused a lot of misery for that family. After the story, my daughter asked what did I expect to come of reuniting with strangers with whom I shared DNA. I came to see that it was probably better not to ring a bell that could not be un-rung, especially since our family struggles to get along with the members we have.