I avoided flowing costumes because of the tripping hazard. I imagine a flowing costume could also catch fire if it was near a flame.
With that being said, I made years of costumes from polyester/ cotton broadcloth. A few things I did....kept Dracula cape knee length and with Velcro at the neck in case someone decided to grab it and hang on. Same thing with Little Red Riding Hood' s hooded cape. White angel dress was a simple long sleeve dress with sleeves wide enough to go over a coat and gathered elastic at the neck.
You can't tell me the synthetic nylon/polyester store bought costumes are any safer than hand made ones.