Sounds like a plan, Jonna. Just make sure there are good air spaces around the roots. Most orchids would rather be too dry than wet all the time. That's why soil doesn't work - not enough air in the mix.
As far as your Vandas not blooming, they might need more light. Vandas are pretty demanding of sunlight. The headache there is how to give them sun without getting them too hot - east facing exposure so they get sun when it's coolest in the mornings? But they do also like to be fed more than most orchids. Maybe keep a spray bottle with some dilute fert in it near them and just spritz
