caring for a sunburnt miltoniopsis

[Kaykay]

Hi,
I've rescued a poor burnt to a crisp miltoniopsis (we've had a lot of hot weather here, and someone has left this poor thing for days on a trolly in 9am-6pm full, direct, summer sun, and as I've never had one of these before, I'd love to hear your wisdom about caring for it. I've cut off the dead flower spikes (2 of them were burnt so badly, they were totally dried out) and cut out 2 now dead leaves. There's still one spike totally intact, and the odd singed marks on other leaves. There are quite a number of healthy ones still though. I gave it a good water, then left it overnight in my kitchen sink to drain well (but also quite a humid room)
First question, would it be a good idea to give it a nice big dose of orchid food to help the recovery?
Secondly, when I turned the pot over, I noticed something looking like florists' oasis packing the bottom. Is this a good plan for one of these plants? It seems to go against anything else I'd do to care for my other 'chids (Phals, Paphs, Vanda) but they are very different types I think! Is repotting a good plan right now, and if so, what would you more experienced keepers recommend?
Thirdly, almost all of the aireal roots are also scorched (I think) They resemble strands of shredded wheat breakfast cereal. One or 2 went green on watering, but the others have stayed yellow/singed and crispy brown. Should I remove these, or just leave them?

thanks for all your thoughts.
Kay