SamanthaT,
Your tree does not look too bad to me. Inner "needles" will turn brown over time, no leaf/needle lasts forever. Indoor/outdoor fertilizer sounds like marketing to me. The NPK ratio is more relevant than the name on the package.
Heed GardeningCook's advice regarding placement and watering. It should be outdoors, always. Monitor the moisture of the soil rather than water on a schedule. This forum is replete with examples of Junipers that well meaning owners have pampered to death.
I have a different perspective regarding misting though. Misting can be beneficial to a Juniper in distress. Oh, the moss is not actually living, just topdressing. Nothing inherently wrong with that strategy, especially in hot areas. That loose moss does, however, impede your observation of soil conditions. The chopstick method is the way for new owners to go.
Another method is to insert a kitchen skewer or chopstick to the bottom of the pot and leave it there. Take it out daily to check it; if the skewer has soil stuck to it don't water. Touch the wood to your cheek or underside of your wrist, if it is damp there is no need to water.