I live in SoCal by the beach and water my bonsai 4-5 times a week. I have multiple house plants and succulents. Not sure why this is happening

That is interesting. I do the same with mine but they are just fine.

quite simple really: there is no such thing as an indoor tree. They die inside.

The yellowing of inner needles is a normal proces of aging. In several speies of junipers, this happens in one big flush, once a year.

Both are correct. If you keep it indoors sooner orlater the whole tree will go yellow and die.

If you are in Southern California inside or outside, watering 5 times a week is probably not enough. Outside more than once a day may be necessary, depending on humidity.