Not aware of any soundfonts for musescore for this sort of thing—possibly because it's not typically the tool used for chiptune.
If you really want to get authentic NES music, you can use software like famitracker to make it. Has a bit of a learning curve, but it's really cool once you get the hang of it. You will even be able to export the music as a binary file for use in the game.
​
There are two different 4 measure subjects here. I like the first one the best, but the last one has the climax of the subject on the dominant. Let me know what you think.
​
One minor thing I noticed is your pedal notation. It's not wrong at all, but it is a little outdated (disclaimer that piano is not my main instrument, this is just what pianists have told me). Instead, it's better to use something like this:
(First image is what I'm talking about) https://musescore.org/en/node/33126
Material looks good from what I saw so far. Keep writing!
Sure! There was actually no post processing done to pitch shift the vocal lines to the correct 19-tet pitches. I did, however, have the 19-tet parts playing into my ear as a I recorded them so that any mistakes I made would be obvious and I would know to give it another go. It's surprisingly easy to develop a feel for singing in 19 though, especially if you first familiarize yourself with its available "MOS scales".
In case you're curious: I wrote the piece in MuseScore3, a free and open source music notation software, using a 19-tet plugin. (You just apply the plugin every time you add new notes, and then it will playback correctly.) It was the exported audio from MuseScore3 that I fed into my headphones as I recorded.
It is still the same chord, no matter how you arrange the notes or where they are played on the piano. You might find this app useful, if you are trying to understand piano chords as a beginner : piano chord trainer.
If you want a serious ear training/sight-singing curriculum, the Gary Karpinsky anthology for sight singing and ear training are used in a lot of college music departments.
https://www.amazon.com/Anthology-Sight-Singing-Gary-Karpinski/dp/0393973824
If possible, look into taking a class at a local college. Otherwise, check out an orchestration textbook like https://www.amazon.com/Study-Orchestration-Third-Samuel-Adler/dp/039397572X/ref=sr_1_1?ie=UTF8&qid=1467290384&sr=8-1&keywords=the+study+of+orchestration+samuel+adler
That's what a lot of schools use when teaching orchestration. This will help you learn how to write for specific instruments and covers many techniques. Another great way to improve your orchestration is to study scores. If you are looking for a specific "rich sound" like what you hear in whomever's symphony no. 2, then get a score for it and listen to it! I advise listening to it once without a score or listening but not looking too closely at it and following along. Stick a page marker in the book on a page you find interesting or when you hear a sound you like, then come back to it and try to figure out what you like about it! The textbook will help a lot because it can inform you of a technique you may be unfamiliar with: what it's called, and how to notate it correctly. If you get a copy of the book with CDs you can hear some examples of everything in the book.
Another way to help if you can't find or afford the book is to find someone who plays the instruments you're writing for and go to them with pen and paper and ask them "show me every interesting trick or technique you know how to play." have them spell out whatever it's called and show you how you would notate it as well.
And like composing any new thing, the more you do it, the better at it you'll be.
Depends on what sort of ensemble you plan to compose for.
If you're looking for Orchestration type of composition, definitely start with *Samuel Adler's 'The Study of Orchestration' * http://www.barnesandnoble.com/w/the-study-of-orchestration-samuel-adler/1114581471
If you're looking for a wider view of music as a whole, and (mostly) all instruments, go for the Cambridge Music Guide http://www.amazon.co.uk/Cambridge-Music-Guide-Stanley-Sadie/dp/0521399424
If you're looking for a more contemporary compositional knowledge - pop, rock etc. let me know and I'll dig out my books