The shields on a ship use a series of runes and gems embedded into a magical projector of sorts. Magic is then supplied via a manafusion reactor or other means of magical storage. And yeah, each Iscandarian has a mana pool that slowly refills overtime.

As for giving it to other species, its a area the Iscandarians are exploring. When it was gifted to them by Faust she linked it to the souls or spirits of the Iscandarians. The Iscandarians were planning on mentioning this to the Nouvelle queen in private and saying that if the could prove they were trustworthy then they would be the first non-Iscandarians to have it.