Kristin, my mouth has always been crooked when I smile, I noticed it years and years ago now when a guy I was dating at the time pointed it out, (he thought it endearing) He would talk about my "captivating crooked smile" in front of my daughter, and she'd be like "yuck! he's too nice! and mimic him when he wasn't around LOL If she'd think she might be in trouble for something she'd say, come on mom, show me that captivating crooked smile of yours!
I also read a question you'd posted about the tongue tremor. Doctors don't seem to care if there is movement when we stick out tongue's out, but rather when it is at rest in the mouth.
I think that hormones during pregnancy can mess things up for us a little bit. Do your best to focus elsewhere and probably every last symptom that is bothering you now will disappear after the baby comes.
To specifically answer your question about one side of the mouth not responding equally to the other, no, that is not an initial symptom of bulbar onset. If your entire side of your face becomes obviously asymmetrical, then it still wouldn't point to bulbar onset, but maybe something like Bell's palsy, that is not fatal, and people usually make a complete recovery from.
These are the best times of your life (I know you're probably tired of hearing it, but its true) Enjoy having a little one to read to and rock and play with, you're very blessed to have that, and then you've got the next baby on the way! Keep on making the scary faces too! Has your daughter decided what she wants to be for Halloween?
Take care :smile: