Two minutes in and already some.major issues.
Okinawa is formally created in 1879, yes, but that has nothing to do with Satsuma. You are likely confusing the fact that Satsuma did have a complicated administrative role in Ryukyu starting with the invasion in 1609. Moreover, before Okinawa PREFECTURE was created Japan established Ryukyu HAN (domain) in 1872, so at that point it was no longer a 'kingdom'.
Your discussion of language vs. dialect is very messy and inaccurate. There are a multitude of Ryukyuan LANGUAGES in the Ryukyu islands. Kunigami language is different that the 'Okinawan' language of Shuri which is quite different than the languages of Miyako or Yonaguni. I say LANGUAGE because they are not mutually intelligible with each otherm Within those respective communities there are dialects, to be sure.
I would recommend doing some more research and getting your facts straight before you try to speak on the topic in great detail. I think your intentions are good, but misinformation helps no one.
Akamine's book The Ryukyu Kingdom: Cornerstone of East Asia Would be a good place to start for history. Look into the work of Byron Fija and Patrick Hein for more language stuff.
Does the scholarly section of Google help any? I haven't looked through it myself but here you go:
http://scholar.google.com/scholar?hl=en&as_sdt=0,5&as_vis=1&q=okinawa+post+war+history
Tabata Home Center in Ishikawa or Makeman would be the first places I'd look. You could also look at Sun-Sea (turn right when leaving Kadena Gate 3 and it'll be the green building on your left). I see a couple on Amazon JP, but they aren't cheap (https://www.amazon.co.jp/Eagle-1656MBLK-Black-Metal-Capacity/dp/B00MPHYBW4/ref=sr_1_35?ie=UTF8&qid=1491340751&sr=8-35).
This might be the most obscure thing I've ever seen requested here lol. You might have some luck on Amazon JP though - https://www.amazon.co.jp/山崎産業-C3-000U-MB-清掃用品-コンドル-自由箒B/dp/B0049JWELG/ref=pd_sbs_60_3?_encoding=UTF8&psc=1&refRID=EAE8VEPESW84DAXPQF9Q
They might even be on the US Amazon. I'm guessing you're not looking for a normal large push broom used on store floors and stuff, but that smaller, thinner one common in Japan.
It's available on Japanese Amazon. If you're that keen to get it, you could try using a forwarding service like Tenso to get it delivered to you in the US. Costs will go up of course. Additionally, Japan Post still have the US on the no-send list for parcels so I don't think you'll be getting it any time soon anyway.
I'm not sure if you meant to ask me, or u/g_reat0, so apologies if I'm sticking my nose in.
To be honest, I'm not sure what might be the best books in Japanese to suggest. It's funny - in a way, it's sort of the reverse problem. While in English there are truly only a handful of books to recommend, and none of them are really ideal, in Japanese there are so many books that it's hard to know which ones to recommend as definitively the best.
For an overall survey history, honestly, I'd probably just go with whichever 「沖縄県の歴史」or 「琉球王国の歴史」or the like you can find. I guess the 2010 沖縄県の歴史 by Asato Susumu (https://www.amazon.co.jp/-/en/%E5%AE%89%E9%87%8C-%E9%80%B2/dp/4634324717/ref=sr_1_2) might in some senses be the most standard, and one of the easiest to get a copy of, since it's part of a 47-part series, survey histories of each prefecture.
I have not myself read different survey histories through enough to really have a solid sense of which ones include what aspects or interpretations and leave out what aspects or interpretations... though if one is willing to spring the money for it, the 近世 (early modern) volume of the official 沖縄県史 is really new, and probably reflects the latest scholarship better than almost any smaller, cheaper, book.
That said, 琉球の中世 is probably a good one for getting a sense of some of the key arguments from Maritime Ryukyu - as argued by leading Japanese/Okinawan scholars - and there's a really inexpensive, really general-audience accessible book by Uezato Takashi, 誰も見たことのない琉球, which introduces a lot of the basics - what are gusuku and how are they different from Japanese castles? In what ways was Ryukyu rather Japanized or Japonic in its cultural character before becoming more strongly Sinicized in the 17th-19th centuries? And so forth.
If you can understand Japanese, RBC Radio streams on Tune-In. Not sure how useful it will be for events, but they might have a show that talks about it - https://tunein.com/radio/RBC-Radio-738-s98232/
Okinawa is a great place to go. (But I was born here, so I may be biased). Especially for a foreigner (at least that's what my foreign friends tell me). Because of the military influence, Okinawans are used to seeing foreigners and I understand that it's a little more friendly when it comes to English.
Also, Japan is super safe and the people are friendly and usually willing to help. I think it's a great country to start your travels to ease you into the traveling spirit.
As far as your Japanese goes, my boyfriend uses an app called Memrise (https://www.memrise.com/) to help with his Japanese. He's been using it for about a month now and his Japanese has improved so much more than when he was using Duolingo.
The only downside I can see to Okinawa being your first place is that, like someone said on here, it's a very car oriented country. Unlike mainland Japan, public transport isn't great because most people just drive everywhere. The culture is also slightly different from Japan, so if you're looking for that authentic Japanese experience, you may want to go to mainland.
I'd never seen such a thing. Most people use small little mini wallets just for coins.
Anyways, this looks like it. The phrase is 小銭入れ or 小銭ケース. Coin = kozeni
I didn't know your exact dates so I played around with the 15th and 20th. Found plenty of flights through the month to the Tokyo area. https://www.google.com/flights/#search;f=OKA;t=HND,NRT;d=2016-12-15;r=2016-12-20
There's only really 3 "actual" phone carriers here - AU, Softbank, and Docomo. I believe Y! Mobile operates on Softbank's network so it should work fine, but you'd want to bring your phone in to a shop and have them test their SIM card on it before you sign up.
The MVNO carriers like Y! Mobile and UQ and such can have cheaper prices than the main companies, but they have fewer bonus features and promotions too (with AU, I got a contract for a SIM card for my iPhone and they gave me an Android phone for 1 yen because I have a kid under 15 years old and since I get fiber internet through them, that was discounted too). Worth shopping around. Last time I was on Softbank in Okinawa though, their signal wasn't great in some parts of the island and their speed was consistently the lowest. It could be improved now though. I don't think I've ever lost signal with AU and only rarely with Docomo.
For VPNs, it's hit or miss. Streaming companies have gotten really good at blocking VPNs. I can't speak for ExpressVPN, but I had success watching US Hulu with NordVPN. I got a Sony TV that runs Android, installed the NordVPN app on it, and it worked perfectly.
Feel free to DM me if you have more questions!
I ordered it from the Japanese Amazon
found out that you can order through Amazon UK to get one online. Amazon UK So that's an option.