Quick question,

Do terrain chunks, (1x1 Square of Terrain) have multipul heights if they contain portions of different terrain heights? I.e jungle grass to mud, ect.

EDIT: I just realized if they were in the same chunk then they are the same height of terrain, Correct?

Yes, I think the program HawtTiles(you've gotta ask Farty for it) allows you to see the height of each individual tile.

EDIT: By yes, I meant to the edited part, the entire tile shares the same height

and if you have a dirt tile next to a high dirt tile and have 2 units attack eachother, the effects of highdirt will be in affect so the unit on that will only be hit 30% of the time, even though there is no actual cliff visible.

duh.

But what if the a unit(Ultralisk) is half in dirt, and half in high dirt?

Does it even apply to melee units?
Otherwise, you could just test it yourself.

Most likely it is decided based on the unit's center, which is one pixel, so it can't go either way.