Poor, sick Cattleya Maikai

[Meezer24]

Hello! I'm new here and I would love some help with my new Brassocattleya Maikai.
I've been tending to orchids for about three months now. I purchased a "Just Add Ice" orchid from my local grocery store. I quickly became fascinated by orchids afterwards. I re potted the phal (which already had lovely, green roots and no rot evidence on the roots) in sphagnum moss. All of its 9 blooms have opened and have been ever since! I told myself if I could care for the phal adequately, I could purchase a more expensive orchid from a grower.

So, three months later I brought my phalaenopsis to a place called Little Brook Orchids in Lancaster, PA. They were very knowledgeable and helped me find a good orchid for my growing circumstances (a warm home under a bright growing light. I have an anthurium and bromeliad also thriving under these circumstances). They also told me my first phal was in exceptional shape. They sent me home with something called "liquid ladybug." I told them I never had a problem with insects, but brought it anyways. After smelling the stuff I imagine it is made out of peppermint oil and other natural plant oils. I came home with a large Phalaenopsis lueddemanniana with one keiki, four spikes and a Brassocattleya Maikai which was quite small.

Well, from what I've learned, you ought to take your orchid out of its potting mix and inspect the roots as soon as you get home. I did so and I was very frightened by what I saw!
Within the large pot I found:
A TON of tiny white spots moving within the potting mix all about the size of the head of a pin, no larger. There were also a couple of tiny spiders (not spider mites--definitely spiders) and a large, worm like bug which curled up at the bottom of the pot.
I quickly re potted both.
The potting mix (a decent mix made of barks, charcoals and packing peanuts) was soaking wet and both the phal and cattleya had some serious areas of root rot. However, the phal had some beautiful healthy roots. I cut the rotted roots off and I have been keeping an eye on the roots of the phal. It is doing very well. The keiki seems to keep on growing. I mist it's roots daily and let my new potting mix dry out thoroughly (it is the American Orchid Society mix--bark, charcoal, some type of crunchy plastic material). The mother plant has lovely new root growth and is doing well. (Side note--the keiki has two leaves and two roots about an inch long with active growth--too soon to repot?) \

The poor cattleya was in much poorer shape which brings me to the important part of my post. Though I re potted it in dry mix and let it dry out between waterings, its roots still rotted almost entirely. It has an old spike which has been cut and is about 2.5 inches long, a healthy grass green leaf color (3 leaves). However, today I checked the roots and they were all total mush except for three nubs about half an inch long. I cut off all of the rot, and put it in a quart ziplock bag next to some moist sphagnum moss. The tallest leaf sticks just about an inch out of the top. I have it on the floor propped up next to my anthurium so it is farther from the light than the other two phals. Am I on the right track to trying to save this orchid? Do you have any additional advice based on the information I shared? I had no evidence on either plant of any insects after I re potted the plants in fresh mix. I sprayed both with some of the liquid ladybug right before re potting.
Thank you for any and all advice!