Beginner here: Paphiopedilum, Miltoniopsis, Phal rot and orange pests

[s3attlite]

Hello orchid people!

This is my first post! I am very new to orchids (~6 months) but not to plants in general and am having some issues. I will try to be as detailed as possible since I know orchid people tend to be high-maintenance...

My style is usually to repot as soon as I buy whether in bloom or not (so, overly fussy). I made some crucial beginner errors that I can see so far: no quarantine, using miracle gro......, over-fertilizing, and too much sphagnum moss. But I'm looking for confirmation, as well as tips and advice from people with experience growing in a similar climate to Seattle (dark and humid winters, relatively dry and mild summers).

My micro-climate:
Seattle: about 150 sunny days, just under 100 days of rain, and just over 100 cloudy days.
Apartment has mostly west facing windows. Temp stays between 55-70 in winter, and 65-80 in summer (sometimes with the occasional extreme). Humidity hovers around 60-80% most of the year, lots of condensation on my windows during winter.

My collection:
Dendrobium Amethystoglossum
Den. Fire Wings hybrid
Den. Kingianum (bought online and on its way!)
Label said "Miltonia Wasnernoff Celle" but am pretty sure it's a Miltoniopsis. It has not bloomed so cannot confirm this label.
Paphiopedilum Maudiae type hybrid (lost the tag!)
Oncostele Catatante
Cattleya Walkeriana
and several Phalaenopsis misc. hybrids.

Miracle Gro: My paph hybrid was purchased at discount because the nursery broke the flower spike. It was potted in pure sphagnum and took about 8 or 9 days to dry out, which was too long for me, so I put it in half miracle gro "bark" (I know better now!) and half moss. This mix took 6 or 7 days to dry out. I believe mold that grew on the miracle gro traveled up the fans and to some of the roots. When I unpotted, the 4 fans fell apart into 3 pieces. I re-potted them separately in different set ups to see what works. The middle fan seemed slightly rotted, so I'm not expecting that to bounce back, but there's a new growth on one fan, and the piece with two fans has a new root showing. Am I correct in assuming it wasn't a moisture issue on my paph, but a miraculously gro-ing mold spreading issue?

Orange Pests: appeared on the roots of one of my phals so I treated it and watched for a few weeks. I noticed another phal's flowers wilting out of sequence to when they bloomed, so I un-potted it to find orange dots along the roots. I decided to treat the whole lot with a pesticide (sorry green people) in fear that I would lose my entire collection. They seem to be gone, but I assumed they were a type of spider mite and hope that one application of the pesticide will be enough. Should I follow the label and treat again in 30 days? Or am I safe from what I assume are the dreaded false spider mites?

Too much moss. My miltoniopsis was not in bloom when I got it and the bark/moss smelled terribly. I potted it in a similar bark/sphagnum mix, but I noticed orange rot at the base of the leaves/pseudobulbs and the bad smell returned. I ended up re-potting it in fine bark and perlite when I bug-sprayed my plants. The smell and orange rot are getting better but I was wondering if the pseudobulbs and leaves rot if they are potted too deeply in moist sphagnum. I'm not watering this orchid much to allow the rot to dry out, but I'm guessing I will need to water this bad boy in this set up fairly frequently. Has anyone else had success growing miltoniopsises-miltoniopses(?plurals?) in bark?

My favorite, the Den. amethystoglossum is confusing me. I got it a month ago as a spectacular juvenile just reaching blooming size; there were between 25 and 30
plump pseudobulbs less than 14 inches tall and zero signs of old flower spikes. It is now spiking like crazy after it went through a rather violent re-potting and significant shriveling. It looks like it was grown originally in pure sphagnum, then potted directly into coarse bark, and again into more bark. I could see each layer of root growth around each layer of media so I spent about 30 minutes removing 2 and 4 year old media based on the dates on the tag. Almost all of the older psuedobulbs are slightly to extremely shriveled now but none of the new ones are after I had to hack away at the root system. Is this orchid spiking from stress or is the orchid just enjoying my relatively cool apartment? The older pseudobulbs are not plumping up, but the new ones are not shriveling, even with daily waterings... Should I expect them to get better after blooming is done and there is new root growth? I am tempted to hack all the spikes off and force vegetative growth... Is that advisable when we aren't quite into spring up here?

The pic of the den. amethystoglossum is a month old and does not show shriveling or spiking.

Any help would be... helpful! Thanks!

-Ed