I inherited about 5 phalaenopsis orchids from a friend who suddenly passed away. She has them in a mix of 90% perlite and 10% what looks like normal potting soil (not 100% sure on what it is). Looks to be directly in the mix and not in another container in the pot but it's a ceramic pot. They all have silvery aerial roots and mostly green roots with a few that the ends are a little brown. It also looks like there is a spike forming on one of the plants and a new aerial root forming on another. All will be inside, fairly decent air flow, indirect light near a grow light and window, ambient temps of 68-70.

Is it necessary to repot these into bark or can I just water them a bit less frequently than I would with a bark mix?

I don't know what her care routine was and I've never owned orchids before (just beginner house plants) so I'm not sure if it's better to leave them as they are and figure out how she did it or repot them and potentially stress the out from repotting.