上下左右 (じょうげさゆう). Means "top, bottom, left, and right". It isn't used very often, but it's useful for talking about web design, which is how I first encountered it.
拘り (こだわり) when used for food. It's easier to translate it as a verb (拘る), which means to be particular about something. 玉子に拘っている can very simply be translated as "We're particular about eggs", but 拘りの玉子サンド is much more difficult to translate. In this usage, it means that lots of care, thought, time, and/or work has been put into getting it right. There are a few translations you could use, but I don't think any one of them had quite the same nuance. Jim Breen dictionaries translate them as "speciality", but I don't think it captures the original meaning at all. You could translate it as "artisanal" or "finest", but that gives it more of a high-end or luxury sounding nuance. "Meticulously crafted" is also close, but that sounds like something very complex or elaborate, whereas the original can be used for simple things.
I was once wondering around a neighborhood in Tokyo and passed by a group of friends who were saying goodbye to each other. I heard one of them say “お疲れヤマ”. I stopped, wondering if it was some strange kind of slang or regional variation, but she then started laughing and said “お疲れマウンテン”.
One of my Japanese teachers pointed out that it’s often used in sentences like OO家族代々墓, which makes it sound like " the OO family are massive idiots.
I also thought 五十五 sounded funny when I first learned it, because I thought it was supposed to be pronounced like “go Jew go”.
It probably doesn’t make any sense noq considering how quickly internet language changes, but I learned the word for ambulance (救急車 きゅうきゅうしゃ) around 15 years ago, and at the time QQ meant crying, and was used to call people emotional crybabies. It reminded of the term “wahmbulance” which people would use when someone is being whiny.
手紙 is the direct object. 家 is the place it was sent to, so I suppose that counts as an indirect object. Sentence order for Japanese is very flexible (although the verb must always come last), so I wouldn’t worry too much about memorizing any particular order beyond Subject-Object-Verb.
Edit: I took a look at the source you gave, and I think you should probably disregard this sentence pattern. It’s clear from the purpose of the lesson that they were purposefully trying to shoehorn から, へ, and に into single sentence. I don’t think it sounds particularly natural.
As I mentioned in my other comment, I assumed they were the same, but several sites said they were different things. “American coffee” is a weak brewed coffee, and Caffe Americano (アメリカノ) is a diluted espresso, which is actually stronger than most brewed coffees, at least in terms of caffeine content. Japan has アメリカノ too, and in my experience it’s much more common.
I thought maybe it was supposed to say Americano, but it’s not the same. There’s an explanation here. It’s made from light roasted beans, and they say it most likely got it’s name from Americans in post-war Japan brewing coffee with lots of water or diluting it further before drinking.
I’m not American, but the name sounds a little judgemental to me.
!japaneselanguage is more active. It’s a community for discussion of the Japanese language rather than just learning and study methods, but plenty of the posts are about learning.