Cotton would wrinkle even worse than Tetron, but absorbs sweat pretty well. One option is to wear a cotton hakama for regular practice, and save the Tetron one for more-formal occasions.
There are hakama available that have the pleats "sewn in" so that they don't get lost during laundering. The best option for ironing the pleats on a regular version is just to take your time and watch where the lines fall. I don't lay mine out to iron it; I keep the pleats pleated and iron through a cotton sheet to keep the creases from getting shiny.
HTH.
Yours in Budo,
---Brian---