My suggestions?
Striga would be "Stree gah," emphasis on the first sylable.
Kheldian, "Kell dee ann", emphasis on the third. As in English, the K ("keh") sound is made by a short click and an exhale, simply elongate the "h" in the normal K sound, but not as much as if you were pronouncing it with an extra H... that is, "kehh", not "keh-hh"
And the paramount cause of this thread, Tsoo:
Having already adopted Japanese speech patterns, I would pronounce this in keeping with those standards. Typically with a Japanese name, the T sound in this would pronounced VERY briefly. It's not so much a "t-soo" noise as it is an S with a hard start.
(As a sidebar, I'm not certain where the name came from, but as "tsu" and "tsoo" are both romanized forms of Japanese sounds, and as "tsoo" itself is an acknowledged phonetic symbol for German ("zu" is "tsoo" in several cases), as well, one just make a random guess and be somewhere in the vicinity of correct.)
