Hi @PeterthePapercomPoser and @Hcab5861!
I've modelled the overall texture and soundscape off of the bass aria of BWV 159 (which is imo the most beautiful aria Bach has ever written). The omission of a harpsichord continuo and the strings "harmonic halo" are both completely intentional - I want the mood of the music to be gentle, warm, embracing.
In addition, I'm a little bit torn on Da Capo form. I think it works well in duets but by default I tend to avoid it. From a singer point of view I don't get excited about singing the first part of the piece exactly twice, and from a compositional point of view, your ritornello theme better be REALLY good to warrant a minimum of four exact repetitions (but more typically six to eight repetitions including fragments), at least for those themes that are tonally closed. I much prefer the scheme of ABA' in these cases (e.g. see the alto aria in BWV 197), where A ends in the dominant and A' ends in the tonic.