Hiya!
Wow... you are using quite a few products! But I guess when all is said and done, I do the same if I'm ironing my hair. I have course hair, a LOT of it, and it's colored. The natural texture is wavy.
First off, it sounds like dryness is an issue. Look at the products your using and look at the ingredients. Do you see alcohol listed anywhere? I was SHOCKED when my hair stylist told me to look at the ingredients of some of the products I was using and alcohol was the 2nd or 3rd ingredient.
Very drying on the hair! Avoid it if possible. Do you deep condition your hair once a week or so? It sounds like you could be overprocessing your hair. Between the heat of the hair dryer, and the heat of the straight iron, you're putting a lot of stress on your hair. Do you straight iron every day? Do you blow dry every day? Do you wash your hair every day?
I don't know if you're going for a real straight look all day, but my hair does do the same thing. I live in a pretty humid climate, and I had mentioned on another post, that if you're going for Jennifer Anniston "straight" Friends hair, well, keep in mind they had to flat iron her hair every 20 minutes to maintain that look she had.
Also, when blow drying, I dry from the top down to the cuticle remains smooth. Blowdrying towards your head will just rough up the cuticle.
I don't know if I've helped with any of the suggestions, but I have a deep conditioner that I absolutely LOVE. It's not cheap, but it works ten times better than anything I've ever bought before. It's from Nexxus, but it's from their organics line called Phyto-organics. I use a very concentrated shampoo called Hydruss and a conditioner called Enphuse. I only know of one place near where I live that carries it, so if you have a stylist, ask them if maybe they can order it special for you. Just a thought.
Good luck!!! Hope you get the look your going for.