A.W.
For sleep, there are two books I would recommend.
1. Healthy Sleep Habits, Happy Child
2. Baby Wise.
Regarding the food refusal and gagging:
My daughter does this too.
Here's what I figured was going on. When she isn't feeling the best (tummy ache, teething, a cold, or whatever) she refuses to eat. Just the same way I respond when I'm not feeling well.
She eats when she's hungry...once she's feeling better.
I just keep offering the food...if she eats...Yay.
If not, I make sure I am nursing her regularly and at least she is getting something.
The most important thing is that she gets fluids so she doesn't dehydrate.
Like you, I tried giving my daughter yogurt and she threw it up. I think that means she's just not ready for it.
I agree with the person who recommended the well mashed avocado...they are sooo good for babies and my girl loves them!
As for the added cereal in the bottle, that can be very dangerous. Please google it or read up on this on any baby website. It is NOT recommended.
Have you tried plain cheerios for a snack at the high chair?
Hope this helps!