1. Are there any books/websites/resources you would recommend for me? (If it's the name of a book, please supply sufficient info so I can order it).
Yes. I listed some below. There are many more, but the more specific your question the more useful the answer will be.
2. How can I improve my sight reading skills? My musical theory skills?
Get Richmann’s book (“Super Sight reading secrets") and follow it. See the links below for a fuller discussion.
3. If I were to get me a piano teacher, what should I tell him/her about what my skill level is? (Getting a teacher may be a little challenging, as I live in rural Japan at the moment).
Do not worry about skill level. Instead make a selection of pieces (no matter how difficult or easy they maybe) that you really want to play. Take this list to your teacher and ask him/her to devise a plan that will give you the resources to play all of them. Personally I like to work on 100 pieces over a five year period. The teacher would then organise this pieces in progressive order of difficulty (so that one pieces gives the resources for the next piece), and give you any ancillary material that s/he might find helpful.
4. What other ideas/tips/tricks/advice can you offer me? Please ask for more info if I haven't been sufficiently clear.
He he

. Read my 2190 posts

5. Are there any specific composers/pieces that someone like me could benefit learning from? (I realize this is largely a matter of taste, but I'm open to most things).
Just start with pieces you love. Besides those, the three works that are the foundation of everything else are J. S. Bach WTC, Betthoven’s 32 sonatas and Chopin’s etudes op. 10 & op. 25 (104 pieces altogether). Master those and you will be able to play anything.
Now for some more advice go here:
Start by reading Chang’s online book:
https://members.aol.com/cc88m/PianoBook.htmlThen try these threads:
https://pianoforum.net/smf/index.php/topic,1867.msg14268.html#msg14268(Getting technique from pieces – several important tricks: hand memory, dropping notes, repeated note-groups)
https://pianoforum.net/smf/index.php/topic,1651.msg14344.html#msg14344(How to gain hand independence – dropping notes)
https://pianoforum.net/smf/index.php/topic,1894.msg14707.html#msg14707(mental practice – Glenn Gould interview)
https://pianoforum.net/smf/index.php/topic,2053.msg16886.html#msg16886(How should an adult beginner practice? Chang and practice spot sites)
https://pianoforum.net/smf/index.php/topic,2173.msg18976.html#msg18976(dropping notes)
https://pianoforum.net/smf/index.php/topic,2255.msg19129.html#msg19129(practising long pieces – Bernhard’s approach – Good discussion if one should or should not listen to CDs - Slow motion practice, comparison with walking/running)
https://pianoforum.net/smf/index.php/topic,2355.msg20277.html#msg20277(common mistakes made by students)
https://pianoforum.net/smf/index.php/topic,2429.msg21061.html#msg21061(Technical studies x pieces – the genesis of Studies and how Czerny derived his exercises from Beethoven sonatas - why scales are useless as technical exercises and at the same time essential – Chopin x Kalkbrenner story – Unorthodox fingering for scales).
https://pianoforum.net/smf/index.php/topic,2458.msg21365.html#msg21365(Mental practice – tips for fingering)
https://pianoforum.net/smf/index.php/topic,2485.msg21499.html#msg21499(How to keep a piece in the repertory – learn/forget/relearn)
https://pianoforum.net/smf/index.php/topic,2526.msg21829.html#msg21829(how to organise piano practise in short/medium/long term – Principle of memory retention – Principle of 15 minute sessions – stopping when you achieve your goals. Teachers should teach how to learn)
https://pianoforum.net/smf/index.php/topic,2599.msg22431.html#msg22431(How long does it all take? – several interesting posts here: self-taught students, cake analogy, criticismof ABRSM for expecting people to reach grade 8 in 10 years, learning is not gradual, different ways of learning, and the dispersive method of teaching).
https://pianoforum.net/smf/index.php/topic,2615.msg22522.html#msg22522(Piece analysis – delay going to the piano and spend most time analysing – Comparison with the process of film making)
https://pianoforum.net/smf/index.php/topic,2720.msg23353.html#msg23353(How to practice aim and accuracy – looking at the LH and giving verbal instructions to the RH – Full discussion on left and right brain).
https://pianoforum.net/smf/index.php/topic,2802.msg24467.html#msg24467(When to join hands)
https://pianoforum.net/smf/index.php/topic,2153.msg18525.html#msg18525(Fingering for chromatic scales)
https://pianoforum.net/smf/index.php/topic,2313.msg19807.html#msg19807(Speed of scales – the important factors in speed playing and an alternative fingering for scales).
https://pianoforum.net/smf/index.php/topic,2533.msg21955.html#msg21955(structured plan to learn scales and arpeggios – includes description of repeated note-groups and other practice tricks)
https://pianoforum.net/smf/index.php/topic,2619.msg22756.html#msg22756(Bernhard provides the complete unorthodox fingering for all major and minor scales plus an explanation)
https://pianoforum.net/smf/index.php/topic,2701.msg23134.html#msg23134(Teaching scales – the cluster method and why one should start with B major).
https://pianoforum.net/smf/index.php/topic,2758.msg23889.html#msg23889(scales & compositions – the real importance of scales is to develop the concept of key, not exercise)
https://pianoforum.net/smf/index.php/board,4/topic,4880.3.html#msg46319(how to acquire technique and what technique actually is)
https://pianoforum.net/smf/index.php/topic,1918.msg15015.html#msg15015(Thumb under/over – detailed explanation – Fosberry flop)
https://pianoforum.net/smf/index.php/topic,2024.msg16583.html#msg16583(how to aim the pinky – using the arm to move the fingers)
https://pianoforum.net/smf/index.php/topic,2033.msg16635.html#msg16635(finger strength)
https://pianoforum.net/smf/index.php/topic,2076.msg17157.html#msg17157(Speed – the3 most important factors)
https://pianoforum.net/smf/index.php/topic,2079.msg17335.html#msg17335(Hand tension – not using fingers to play)
https://pianoforum.net/smf/index.php/topic,2106.msg17587.html#msg17587(developing both hands equally – repertory and why the LH is generally weaker – website for left handed pianos)
https://pianoforum.net/smf/index.php/topic,2230.msg20686.html#msg20686(Octaves and fast octaves – excellent post by Robert Henry)
https://pianoforum.net/smf/index.php/topic,2502.msg21594.html#msg21594(Independence of the 3rd and 4thfinger – it is impossible: one should work towards the illusion of independence: it is all arm work)
https://pianoforum.net/smf/index.php/topic,2507.msg21688.html#msg21688(Round fingers – the role of fingers)
https://pianoforum.net/smf/index.php/topic,2552.msg22037.html#msg22037(Accuracy – repeated note-groups, explained here in detail)
https://pianoforum.net/smf/index.php/topic,2581.msg22252.html#msg22252(Question on piano height, octave playing, wrist movement, etc. – Anda gives some good suggestions).
https://pianoforum.net/smf/index.php/topic,1808.msg23879.html#msg23879(Ultra fast arpeggios – slow practice x slow motion practice – excellent post by Herve – Abby Whiteside is also mentioned)
https://pianoforum.net/smf/index.php/topic,1871.msg14384.html#msg14384(Reading notation – Richmann’s book – Cambridge word scramble example)
https://pianoforum.net/smf/index.php/topic,1976.msg15962.html#msg15962(Sight reading – Richmann’s book)
https://pianoforum.net/smf/index.php/topic,2406.msg20820.html#msg20820(the grand staff)
https://pianoforum.net/smf/index.php/topic,2577.msg22247.html#msg22247(Keyboard topography – how to find notes by touch)
https://pianoforum.net/smf/index.php/topic,2713.msg23282.html#msg23282(Teaching bass clef – explanation for the grand staff)
https://pianoforum.net/smf/index.php/topic,2751.msg23710.html#msg23710(detailed explanation of the sight-reading process)
Just the tip of the iceberg.

Best wishes,
Bernhard