Mostly dead roots (Phrag, Oncidium, Cattleya, Laelia, Maxilaria)

[Fishbox]

I've got a bit of a situation, and I'm still on the newish side of things/earning my confidence. Hoping you can lend your collective knowledge to help me navigate this!

After having a heck of a time finding orchids in my area the last few years, I found an orchid show and picked up five plants:

Phragmipedium Mini Grande
Oncidium tigroides
Cattleya Ernesto x Laelia tenebrosa x Cattleya leopoldii
Laelia purpurata
Maxilaria striata

Excitement!

The good news is that the foliage and pseudobulbs are in pretty good shape.

The bad news is most of their roots are desiccated and dead.

However, there was a very tiny green root on the Laelia, which I took to mean it had recently produced the root. This one still had some live roots, or at least live portions, but I'm unsure if this is one which preserves its roots or if anything cut will inevitably die and rot.

The Phrag's roots were brown, but I figured this was staining. Nearly all of them seemed pretty firm, and the sheath wouldn't come off. So I left them.

No new heads visible on any of the plants.

I soaked the plants first, which I believe made my job a little harder in hindsight. I removed the dead roots using a rubbing alcohol sterilized razorblade and sprayed them with 3% peroxide before planting. I dipped them in water after the peroxide spray (to remove any excess/remainder), which I believe was a mistake.

I planted them in Lamberts Orchid Mix:
25% Canadian Sphagnum peat moss
25% Hardwood charcoal
25% Red pine bark
25% Volcanic rock

I added a bit of extra Sphagnum moss to the Maxilaria pot mix, and put a thin layer of sphagnum over the tops of the pots to keep humidity up until new roots formed.

Admittedly I don't love this mix for the Cattleya/Laelia. I have hydroton I could add, or I found another mix that's just wood chips, charcoal, and a bit of perlite. Unsure if it's worth redoing? It's not like there's a bunch of roots I need to pull out to repot at this point.

Everyone is planted in net pots, so there should be decent air circulation around the roots, regardless. I live in a fairly humid climate (60-80%) and run a humidifier during the winter months to maintain 40-60%.

The plants are now sitting at the far end of my living room, opposite side of my NEE facing window to keep the light soft until they've had some time to adjust.

Any further advice? I know I didn't do everything perfectly, but I'm still learning to have a "procedure". This is my first time dealing with plants with this much root loss. My prior Phal's and Oncidiums always arrived fairly established.

I will post pictures of plant + roots in subsequent posts so it's easier to pair the roots with the plant. No photos of the Cattleya, I actually didn't have a pot large enough so I will be potting it this evening.