I am going to install an outdoor toilet for the pool area and just need to know if a pea-trap is required for the underground rough-in since most toilet's have a pea trap built in.
Retopper
I am not familiar with a toilet that does not have a trap in it. If you have a toilet that doesn't hold any water in the tank or bowl then I'm unfamiliar with them. Do you have installation instructions or brand and model?
Generally, you do not need or want a trap underground unless you have a special use toilet.
Generally, you do not need or want a trap underground unless you have a special use toilet.