Vandas are at the high end of the light scale and, except during winter, like to be outside, where they receive good light. Cattleyas and dendrobriums should also be grown in good light. Although there is a temperature-bloom relationship among some, orchids basically are comfortable when we are. Try to avoid temperatures much below 60 or higher than 90 degrees. Heat tolerance rises with air circulation.
Some gardeners apply diluted amounts of fertilizer with almost every watering.
A weak application weekly is an easy schedule to follow. Assuming your Norfolks are in containers, the best thing to ensure winter survival is to move them to a protected area during a hard freeze. If you can't do this, generously wrap the pots and plants and hope for the best. Water the plants well before the temperatures drop. You could prune your trees back, but you would ruin the natural shape.