An Oranda should be quite happy together with a a regular fantail, unless it grows a particularly large wen and begins to have difficulty competing for food. I'd be more worried about your telescope-eyed fish getting bullied by regular fantails, but this may not necessarily happen either. All of the fancy breeds have their own limitations, and should be monitored for signs of problems. About the only thing for certain is that you don't want any single-tails in the mix.