this one also has something on the leafs, I assume it's residue from water.. not sure.

here is the cattleya, it had same root problem. all are currently in bloom.

Going from the top you have a Brassia, an Oncidium Intergeneric (mixed Oncidum Genera Types and a Cluster Cattleya Type (more than 5 flowers in a bunch and probably mixed Cattleya type Genera).
The white stuff on the leaves might be be fertiliser or fungicide or Insecticide, clean it off using milk if it bothers you.
As for culture, depends where you are and the micro climate you can provide for the orchids. Tell us where you are in California and more help will be provided.

los angeles valley area, yes its hot and dry here, I am running a humidifier in the room, there is also AC temperature is around 25-30 degrees C. Humidity at 35-40 percent.

If you really want to grow them indoors and grow them well, they need some direct, filtered sun. Mist the top of the pot every morning just to the point where water begins to run down into the pot.

Next April, put them outside under filtered afternoon sun (some direct morning sun is OK). Increase watering to the point during summer where you are watering every day when it is at least 95F. Purchase a cheap misting system with a filter and run it during the hottest days (90F+).

I have a humidifier running in the room and I also moist the top of medium every other day. they are under day light lamp 60 watt, for about 10 hours a day. :D