I would suggest that Stelle matutine stands for Stellæ matutinæ (GEN., DAT. s. or NOM., VOC. pl. of stella, æ matutinus, a, um), rather than the VOC. s. of a *stellus, i matutinus, a, um. E is a common contraction for æ (and œ), in mediæval Latin at last.
The Morning Stars
[O] Morning stars
...
As for luce, it certainly stands as the ABL. s. of lux, lucis, rather than as the VOC. s. of lucus, i, which means "sacred wood". It is with light that the darknesses are drove out.
Omnia (the NOM., VOC., ACC. n. pl. of omnis, e) doesn't agree with mundi, which is the GEN. s. of mundum. (Omnia might however agree with aurea as a n. pl. of aureus, a, um). Omnia probably stands for something implied like omnes res.