My cat orchids do well with a boughten mix. I may add some charcoal if they don't have any of that. They like a very barky mix. I have one blooming right now with 4 blossoms on one stalk!!

While they would very likely be fine, orchids are perfectly content in bark so there is really no need to change.

I could see an amended gritty mix working for oncidiums, which have finer roots and higher watering demands than others, as well as paphs (your lady slipper), which is a terrestrial orchid (sort of ... they still do not prefer actual soil), and might like it. Still, I'd add larger water-retentive content to that mix, like a small bark chunks, charcoal, and larger size perlite. You need it to be airy.

I wouldn't think it would be a good environment for phals or catts at all.