I'm interested in getting some more fun in on this seasonal template and I just hit 49 finally so I can do local deployments. But I was wondering if it was considered not kosher or bad mannered to create a tournament styled like the current season while it's going on?

no its not. feel free.

It's pretty common for tournaments to be made shortly after new seasonal templates come out and for past seasonal templates to be reused if they were popular.

Sweet, thanks!