This port is shaping up pretty well, but it still has a few issues that prevent me from accepting it.
The biggest thing I notice is that the optimization could be much better.
First, there are a lot of repeating sections that aren't looped, so these should be taken care of. Don't forget to use superloops as well, like in the section with (1), or on channel #5 for example. Superloops are a second layer of loops that can include regular loops within them, or vice-versa.
Second, a lot of your loops actually end up taking up more space, namely all of the ones that are one or two notes repeated two or three times. Because these patterns contain few notes and repeat very few times, using a loop increases the insert size. For single notes, the threshold where loops start taking up less space is around 8 notes; if you have more than that, that's when you should start looping individual notes. When in doubt, insert the port once with the notes looped, and once with the notes in full, and looking at the insert size in AMK's results, see which one takes less space.
Third, once you look into these two things, make sure you add label loops where you can so you don't keep redefining loops and increasing the insert size. Just remember that superloops cannot be called with labels.
Next, there's some other minor issues with the port.
First, this port uses #optimized even though #default seems to insert fine. When possible, you should try to use #default since the samples are of a higher quality.
Second, I notice a "SMW Flute.brr" in your samples folder, though it seems to sound slightly different from @0. In any case, if you want to include #default samples while you have #optimized loaded, you can do it more efficiently as I've mentioned here.
Third, the main @5 melody's notes seem to cut out much earlier than they should compared to the original. I'd remove some of the unnecessary rests you've got there.
Fourth, and this is somewhat of a personal taste thing, but the accordion sample you've used is a little sharp at times, especially compared to the original.
Fifth, I believe I hear some wrong notes here and there, such as around 0:41.
Sixth, this port could use some vibrato. Comparing to the original, the flute section has some noticeable vibrato.
One last thing tip I could give, especially in regards to stuff like instrument choice or the @5 cutting out early, is that you shouldn't overrely on the sheet music or any other reference you use. While it's definitely a plus to have and can make things easier, make sure you listen to the original song repeatedly as you're porting to better get a feel for how things line up. Sometimes you'll have to fix up note lengths, or fix an incorrect note or two.