On Ethnicity, I usually create Sims of whatever ethnicity strikes my fancy during creation, as I build their back story. My Simville is pretty much flush with anything you can think of; and they are free to engage with any other ethnicity as they so desire- or, y'know, if opportunity (frequently) comes knocking! (Walk-bys make the game hilarious when I set up the goal to greet everyone who passes the house).
I suppose I may be too thoughtful in this, but "culturally" I suppose my Sims follow a predominate North American "culture", with back stories as fits their character. I would find it too difficult/possibly derogatory to attempt to impose cultural norms from a "culture" to which I was not an insider. Though that may be a hallmark of good writing, I find the whole concept too problematic for a Sims game. But if for whatever reason it creeps in, due to back story or something else, I will do my best to support it (though that would likely mean significant research outside of The Sims).
And, also in the interest of relaxing, I generally do not include socio-economic status. I like to pretend my Sims live in an ideal non-captalistic society where the needs of each can be easy and immediately met through a mobile device, and furniture/appliances/clothing can be beamed through the power of science, where it is needed/wanted. This allows me to have my Sims express themselves, and their personalities, in their surroundings- maybe someone prefers grungy punk, and another likes Mediterranean themed homes. I find it more enjoyable to 'see where it goes', assuming no economic, or social, limiters.
As for religion, I don't much care. Christmas, in particular, may have originated as a Pagan holiday, became appropriated by Christianity, but currently Christmas is nothing more than worshiping on the alter of Capitalism- so I find the whole absence of using 'Christmas' to be a rather falsely grown problem- if anything it further shadows the current consumer-normalised nature of Christmas.
For the other religious holidays, during the northern hemisphere's winter, I equally ignore their featured items. Though I am glad they are there for others to make use of, if they so choose, I myself do not make use of any of the 'Winter Holiday' themed items, unless they fit the area more generally (those snowflakes will be pretty rocking, I think, with some disco lights and an indoor ice rink!). Otherwise, my Sims are not religious, though perhaps they believe in a pantheon of deities? Oh that might be interesting actually- I should start a Sim cult to the gnomish pantheon. Maybe I will wait for basements though, so I can build creepy-gnome shrines, with llama-sacrificing alters hidden deep under a particular community lot. Haha, oh my that's ridiculous.
But I digress, for 'in real life' religions, they don't make an appearance in my Simville. I certainly don't view myself as their God, perhaps just their narrator.
Probably, 99.99% of my Sims are male, and of that they are all either bi or gay- wait save one, I have one straight male Sim (not really sure what I am going to do with him, but we shall see. Maybe he'll populate the town with very attractive children). They are free to, if they so choose, engage in premarital/extramarital intercourse which any selection of the towns male or female residence, but generally I only have them marry each other as I find the townies to be, well, unfortunately butterfaced. So I guess I am not particularly disinterested if any of my Sims want to 'get it on' with women, and am quite happy for them to express themselves as their little algorithms desire. Illegitimate children might add some interest to the game, as well.
When it comes to same-sex pairings, though, I don't assign masculine/feminine roles. Rather the characters themselves have personalities. I try to shy away from classifying anything as a masculine or feminine 'action'; likewise, if that was a tongue-in-cheek way of asking "who's the top", I guess they flipflop. :P Who ever owns the bed they WooHoo in, gets to be in charge- to their mood/preference at the time.
An excellent set of questions; I greatly enjoyed reading the other responses in the thread.
