Orpheus - Thanks first for noting the hyphenations. I noticed the errors were in the second scene which I wrote under deadline. As for the vocal lines, I have to admit that this is how I heard it - rather "rigid" only because I wanted as much clarity with the text and a counterbalance to all the activity in the clarinet piano parts. In addition, I liked what Debussy did in his opera at times - with its speech-like vocal lines. I would not want to do it for a long multi act opera, but I thought for a shorter work it would work. I did struggle with writing a more florid vocal line in the second scene ... but what I heard was what I have - I have to admit it isn't exactly my ideal but I think it works. Also, in regard the vocal line, I treated the instrumental part as another character or a reflection of the inner turmoil of the characters while the characters themselves always are trying to keep things together.
For mm 153 onward, I took up a suggestion of the director of the performing organization to drop the accompaniment as he found the text so haunting. I agreed upon reflection - it also serves as a musical metaphor of the family and the ship's imprint being erased. Good point about the dynamics at that range in the clarinet part in measure 40 - I have some reservations but it may be workable, at worst it could be transposed down.
Now you ask about the pitch material. I embarrassed to say this, but it derived broadly from the major minor chords of the opening of the whole piece which I came to thru improvising on the piano. The "prelude" before the fugue is rather a search for fugal subject. You can see by the various stepwise movements covering major and minor thirds - it isn't apparent at times as in the vocal lines the music literally creeps upward. There are exceptions of course but usually when a character's intensity tries to breakthrough a facade of "keeping it together". This section and the fugal subject were developed by ear. The entrances were planned to be a series of consecutive and non-consecutive major and minor 3rds which as I wrote before never reach back to the original entrance. This was to reflect the concept of never coming back to the original home no matter how hard you chase after it.
I will admit I added once in awhile augmented seconds into the vocal lines for a very slight Middle Eastern inflection. The section which follows the fugue was done largely using my ear - I had that clarinet sound of repeated notes with wild flourishes in my head as I used it in my clarinet solo piece (and it is a figure you find in Stravinsky). I wanted the clarinet to use altered scales to suggest slightly Eastern European or Middle Eastern music. This along with the desire to re-employ the opening chords (reharmonized and altered rhythms) to lead to the clarinet recalling a variant of the opening portion of the fugal subject).
As for the next scene, the intervals open up to 4ths - that idea comes from the 1st and second inversion chords I used in the fugue of Scene 1. Some of the spacing in 9ths or 7ths in the piano come from some of the chords which open the opera. The clarinet part continues with 1st and 2 nd inversion chords and the major minor duality.
AS I write I can understand why the vocal lines seem "rigid" as the planning of the vocals lines was different from the instrumental lines. The focus was on expressive lines that would be understood clearly. The pitch material for the vocal lines was far more intuitive - with a general idea to have the melodic curves never getting too active in Scene 1 (with a few exceptions) and allowing a greater variety of contour for the aria in the second scene - yet again with clarity of text the prime consideration.
Not sure if I gave a sufficient answer about the tonal material, if I were to "classify" it I would say it is highly chromatic with ambiguous tonal centers. The harmony was driven by some intervallic characteristics but more motivic development rather than large scale harmonic progression - which is one of the main characteristics of some of my compositions.