Try out Kinetin 3-5mg/l, also you can use TDZ in low concentration. But from my experience i can say combo of Kin and BAP can show outstanding results.
We cannot predict the effect of hormones in seed germination of orchids, Because every species respond to a specific combinations of hormone or without hormone in a basal medium... but it depends on the nutrient composition present in the media. Try with different media and combinations of hormones.. then you will succeed...
please study the seed biology of orchids, without seed germination studies you cant really focus on PLB differentiation and organogenesis. Are you using explants other than pod seeds? If yes you an use meristamatic tissues which is free of endophytes.. Any way try to collect literatures based on the orchid species you have selected... again you need a detail study on the effect of media and hormones for either organogenesis or direct propagation....