About a week ago I spotted crown rot on my Phal Cornustris. The base of the youngest two leaves had become brownish and watery. Pulled gently and the leaves fell off. Powdered with cinnamon.
Now, a week later, the base of the two leaves (i.e. the crown) has dried, and the spike continued to grow and formed two buds. Could this be a sign that I managed to stop the crown rot and the plant survived?
you rotted the topmost leaves of your plant.... if you had crown rot; the whole plant will die. The crown is the stem base between the leaves and the roots; then the leaves appear in layers going upwards.
If I understood correctly, the rot was superficial and didn't affect the meristem. Therefore I can expect the plant to grow new leaves eventually.
I can wait. Meanwhile I will enjoy its first flowers.
If your plant is in a lot of stress and is close to dying I would recommend cutting the spike. Blooming takes a lot of energy and you want the plant to put that energy into new root growth and new leaves. Phals can spike due to stress or even when they think they are dying so just because it spiked doesn't mean everything is healthy now. I don't know what condition your plant is in but if it isn't doing good you should consider cutting the spike.
Post some pics if you want so we can see the condition of the plant. If it has good roots and the leaves are fine now then it probably is ok to let it spike.