"The overcoat I inherited from my father, a full-length grey single-breasted, has finally collapsed under the weight of years. I am seeking a new, all-purpose overcoat, as i can only stretch to one this season, which would go as well with black tie as the odd jacket and trouser ensembles that make up most of my day-to-day wardrobe. Which style/colour do you think would work best? "
You're likely to get the most use from another full length oxford gray single breasted.
"I am wearing a silk velvet smoking jacket to an evening event in the near future and I want to wear a cravat under my white shirt. What knot should I choose?
The tied ascot is worn under your open collar shirt so that an inch of silk fills the tie space. Instructions for tieing a an ascot/cravate are here.
"I got a new job today, starting Monday, and from what I understand everyone wears suits. I'm planning on wearing basic navy and charcoal suits, but what about business shoes? I really hate the combination navy and black, and that goes for shoes as well. Would it be totally wrong to wear brown oxfords, chelsea boots (or any other unlaced kind of dress shoe) with navy and grey suits?"
I also prefer brown shoes to black with navy suits but that shouldn't be your first concern. Wear black oxfords the first few days while you get the lay of the land. Your priority should be to establish yourself as a serious player. You can wear brown shoes for decades once you've done that but it's easy to get categorized as a light weight and hard to overcome that first impression.