Jerec did kill Morgan, but they guy you're thinking of was... Rahn, I believe? Anyway, he fought against seven Dark Jedi, cutting one of them in half, and then getting killed by Jerec.
Now, I would normally assume Morgan wasn't a Jedi, however... He did appear as a Force Ghost, and was an underground supporter of the rebellion. He also knew a lot about the Valley of the Jedi, where the Battle of Ruusan took place, and entrusted Kyle with "a lightsaber that once belonged to a friend and great Jedi - Rahn." The one who fought off the other Jedi. I suppose it's possible they had sort of a Master-Apprentice bond going on, as well.
Not to our knowledge.
I am assuming that Qu Rahn discovered how to do the Ghost trick as well, and passed on this knowledge to Morgan Katarn, who was no Jedi but was apparently Force sensitive.
Qu Rahn was the Jedi who tried to fight the Dark Jedi under Jerec. He cut Maw in half; Maw murdered Morgan at Jerec's order.
Morgan's status just makes no sense. I mean, he seemed to have a Lightsabre...
... but the whole thing was just daft plot convenience to allow Kyle to have Jedi powers all of a sudden.
Mind you, fair play to the Jedi Knight FMV scenes; they might not have won any acting awards, but the style in which they were shot were very Star Wars in nature, so kudos for stylistic accuracy.