I'm sure you all know Rand bristled at the notion that she or her philosophy was libertarian.

Too many North Eastern Yankees are migrating to Florida and bringing along their Liberal ideas. The state is loaded with these jerks, and I'm afraid that it might be a blue state for the upcoming election.

My wife is, like me, pretty conservative, while her brother is very liberal. They adore each other, having been very close in age growing up.

My brother and I haven't spoken in years, and it has nothing to do with political views. I had to learn, the hard way, just how toxic a person he is, extremely narcissistic, ruthless, and lazy. After being around me, my wife's unattached friends over the years would pose the traditional question, "Does he have a brother?" My wife's response would be "Honey, my husband is Dr. Jekyll, and his brother is Mr. Hyde."

Fictional character - need no more info
2. No AR characters are Libertarian
3. Same in most families

I have cousins on my mother's side are left-wingers and many have migrated south to become Florida Yankees.
I have another brother who called his apartment complex manager a snowflake and smiled when he told me the man did not like it.

I have one sister, who thank God, is a capitalist and a conservative like I am. But I have a bunch of cousins who I grew up with who are real leftist nut cases. I think that they suffer from a mental disorder of not being able to think for themselves. They are easily led and believe the leftist line that Santa Claus does exist.

Me dino has a brother who votes for Obamanations such as The Evil Hag and sympathized with all the crying snowflakes when Trump won.

AS is. A great book. I couldn’t put it down. I identified with parts of the all the main characters and felt I was actually there among them.

John galt seems to me to be a rugged individualist on a mission. He happens also to be a capable inventor. He is tired of what would now be Hillary and sanders supporters and figured a way to do domestic terror in them and destroy them without violating their rights. (Clever). Dagny and rearden were representative of smart and more normal people in our culture. Galt was obsessed to achieve his goal

Female culture in the USA is really screwed up. Most are weak “stronger together” “make everyone FEEL good” types. Others are entitled by the woman’s liberation movement and are aggressive and kind of hateful towards men. Only a few are just real people who happen to be women

Here's my comprehensive take on John Galt. This is how I like to write biographies of fictional characters: by retelling the story from their POV.

http://www.conservapedia.com/John_Galt

Subtle cultural influences when young were probably responsible. Home life is only experienced maybe 8 hours a day, and influences from an older woman in the house (mom) could be very sugnifucant

Hmm.mm. good point, but, I stand, even if contradicting The Romantic Manifesto.
You say, " different people can find different expressions ..", definitely.
I find AS not naturalistic, and yes there is a strong romantic feel , but it is mainly a warning - go 'that' way and this will happen, explanations are given. The plot develops exactly as the explanations foretold.
'We' were warned, 'we' chose exactly 'that' direction, the result is as predicted, the only difference is in the time scale, in AS it takes a year or so, in life the result is spread over decades.

The OP says we are given very little of the background of John Galt. I think this is deliberate, it prevents the reader judging on that background rather than on achievements. Rand's plot uses identity politics only to condemn the concept.

Growing up in the same house has little to do with how different we all are. Me and my brother have a sister who is off in La La land and a full blown Hillary supporter and we can't figure for the life of us figure out how she got so twisted.

I have to disagree. Ayn Rand said in The Romanitic Manifesto that is it not the purpose of art to be didactic. Unfortunately, she did not expand on that. You should read her own expositions of her theory of romantic art. See CircuitGuy's post on Moral Indignation. Many people came to Atlas Shrugged and found that in there for themselves. Rand discusses how different people can find different expressions within the same work of art.

Four questions. I comment on number 4.
The author is being didactic rather than naturalistic.
Her point is to show the importance of taking a person as an individual, by who he/she is, by achievements and values rather than by who the parents are, their class or inheritance.

Now question 1 and 2, Who is John Galt? He is the inventor of a device with profound implications for energy users, and he explains a set of values derived from first principles on how individuals should run their lives. The implication of the question is- what breakfast cereal does he eat?

I have a brother who's pretty conservative and a sister who borders on communist. It really easy to have two children grow up in the same house and come out differently.