I've never really had trouble with this level, but then again, I always rush through it in the only way I know how. A couple of things:
1) There are no Juggernaughts on this level. Their sounds were given to the S'pht K'r on this level.
2) The red triangles on the radar are not actually made by the S'pht K'r - invisible enemies do not give off any radar signal - but rather by a bunch of enemies placed on a separate, inaccessible portion of the map that overlaps the rest of the level. The result is radar noise that's meant to confuse and/or frighten us.
3) I had no idea about the grenade jumping on this level.
4) Those S'pht K'r move? I never knew that!
5) Nice theorizing.