As a a beginner, the temptation for repotting everything is quite high. I would suggest you learn with one orchid see how it shapes up and attempt the others, so that you can learn and correct the mistakes.
you don't have to flush the plant after soaked in physan.
I would suggest, you observe the new orchids on how they are potted etc and treat them with a fungicide and bactericide and take it into your collection. some orchids don't like to be repotting and repotting could upset their growth cycle.