Very nice indeed! I was surprised by your handling of "Wees ge-groet" for "Ave" and would probably have opted for "Wees(f) ge(c)groet(d) Ma(d)......." but this is not to say that I don't like your innovation!

For "Hei-lige", I think I would have the second syllable "-li" stay on La (same pitch as "Hei-". But, again, there is nothing wrong with your way of doing it.

There are other things I might have done, but this is your work, and it is quite singable. Congratulations!

The vertical episema is used in certain Solesmes editions to indicate expressive lengthening of the middle note of the salicus. This is only because the horizontal episema would be difficult to fit over the middle note of this three-note neume. Unfortunately, this renders the episema in question indistinguishable from the sign used to mark the ictus or beginning of a rhythmic group, which does not per se indicate lengthening.

Of course the general consensus of international chant scholars is that the middle note of the salicus would not have been treated as the longest or most important note of the group according to the earliest known performance practice. (Hence the comment above that the vertical episema "does not exist"). However, if one wishes to adhere slavishly to the method associated with those older Solesmes editions, one ought to include the vertical episema on the salicus (and not on the scandicus).

I would consider leaving the vertical episema on the La after Re in "María" on the first line if your intention is that La be sung expressively. Otherwise I would omit any such markings unless you intend to encourage a particular neo-Solesmes style performance practice.