Had a brainstorm and it actually worked!
Ok, I was trying to make the sketch more robust by using the assembly curve references to dimension to. That way if I deleted the line, the reference dimension would not fail in the sketch or the dwg. Obviously, it didn't like that, and even though I checked and that dim was NOT at the assembly level, somehow, directly referencing the assembly like that threw the dimension into a No Man's Land. So, I "replaced" the dimension at the sketch level to use the line element instead, and all of a sudden now it shows no problem! Huh?!?! In fact, a bunch of OTHER completely unrelated dimensions that would not show in the drawing actually show up now! Man, that's some buggy behavior. Oh, and another thing I found out: There is the same or similar issue with "known" dimensions (Kd#). So, what I did was put in a construction line with a reference dimension, did a coincident constraint to make it the correct length (and thus dimension value), and now it shows in the drawing just fine, and I was able to easily add the GD&T datum to each dimension.
