Firstly we're going to remember the golden rule - Fashion is about one thing: Feeling good and fuck everything else. If you don't feel good in anything you're "meant" to look good in, it's not for you. There's nothing worse than the dude that looks all uncomfortable because his clothes don't feel like a second skin. That said, human brains work a particular way with colours, so this is all conventional wisdom for a reason.
Charcoal suit is an excellent idea, three piece is an excellent idea. You've invested in VERSATILITY (this is a word to which we'll return in this post).
Don't wear a thin tie. You and I are the same, it'll make your head look fat. It's just not worth it when ties are 10 dollars (or like...3 pounds, or pi euros or whatever). Also yes, thin ties and wide lapels make you look like a scrappy douchebag, and this guy is incredibly attractive to start, so imagine how we'd look!
Spoiler:
Buy the following in a thickness that you like -
Black tie, dark blue tie, light blue tie, red tie.
Get yourself some matching pocket squares/hankies. Matching means similar, not exact. Worst case pick up a few plain white cause they'll go with most anything in that charcoal suit. This is your versatility set. You can wear any of those ties with that suit for different levels of formality, and you can do that with a white or black shirt underneath. Get a white shirt and a black shirt, you'll want both for (you guessed it) versatility. Two shirts, 1 suit, 4 ties, you've got yourself like seven different viable outfits! When buying shirts or ties your rule of thumb is "two-and-one".
Two plain fabrics, one patterned fabric. Two dark or muted colours, one bright colour. This means you don't wear a purple cross-hatched shirt with a red striped tie (two bright colours, two patterns, they'll clash and look too busy). Spoiler: Yes yes yes
Spoiler: Jesus God NO!
For the wedding either black or white will work. White is more traditional and more formal, black is more muted and (I'll be honest with you) more likely to hide the stains from the scotch you spill. The big thing is make sure your suit and your black shirt LOOK DIFFERENT. If they blend together you'll look like you're wearing a sack with a tie and you'll lose the whole effect. Plus (again, you and me, mate!) you're a big dude so a flat (i.e. pieces and patterns bleeding into each other) front will make you look like a brick wall or a boulder.
Spoiler: Definitely having fun at this party
Textures and edges will make you look crisp. The pattern helps with this. See how the tie bleeds in to the shirt. You don't want this.
Spoiler:
Paisley is coming back, if you want to get on that train. Here's a hint: You do, but it's not an easy train to get on. Maybe just wait until you've got your feet under you first.
Spoiler: then you do this
Red is not the wedding party colour. I'll guarantee you that. If it is, fuck it, anyone that has red as a wedding party colour isn't the type to get angry with you for wearing red.
Job interviews are jacket and trousers, maybe vest depending on the job for which you're interviewing, white shirt and black or dark blue tie. You want to impress them with your "put-together-ed-ness", not with your flashy bullshit. You also don't want to risk them not liking something. They might really hate red ties or garish shirts or whatever, but nobody hates standard dress. It's the safe play, then make up for it with your skillz.
Casual is super easy for you! You know why? VERSATILITY! Some people say you can wear a charcoal jacket over jeans, but they're wrong. Not because you can't, but because why would you when you bought a three piece?!
Spoiler: AWWWWW YISS!
Last bit of advice: Black shoes, man. You want to go burgundy? Fine, I won't hold you back, but if you wear brown you'll look just terrible.
Spoiler: You can't prefer the right. Human brains aren't built that way
Cheat sheet:
- Two-and-One
- Tie as thick as your lapel. Thicker knots are better (full windsor, really)
- ONE point of attention. A cool hat, a fluro paisley tie, a bright coloured square, but never all three. ONE. You are not a clown.
- Complementary, Triad, and Analogous colours. FUCKING LEARN THIS.Best 10 minutes you'll spend, easy as SHIT to remember, and will make life easy.
- Nobody wants to fuck the sad guy. Make sure it fits comfortably and that you enjoy wearing it.
- $200 on a tailor is worth more than $1000 on a suit. If you get that charcoal tailored for a few bucks, it will make such a difference, and you can wear it everywhere.
- Hang up your suit when you get home, not matter how trashed you are. Drycleaning is expensive and bad for the suit, you only really need to wash an occasional suit twice a year if you hang it up.
- Feel good. Fuck everything else I wrote.
Black connie lows are a good choice. They live forever, never go out of style, and look great with jeans. Literally any canvas shoes will work, if you want to save some cash. Be aware that cheaper canvas shoes usually use a cheaper sole, so be aware of that when you're on your feet a lot. 
They're too formal and you limit your choices of "causal" pants.