Don't worry about that. On oncidiums that get enough light to bloom, you will see 'sunspots'. It is normal and if your foliage was pretty (without spots) your oncidium probably would not bloom because it is not getting enough sunlight.
The brown tip of the leaf might be a bit of fertilizer burn. This is caused by salt build-up in the orchid medium. If you have not already done so, flush the pot out with clear water. Just run water through the pot for a few minutes. If you are feeling adventurous, I recommend repotting your orchid. )I always try to repot all new orchids. It is a matter of safety for my other plants as well as to let me see how the roots look and if I need to do anything special.)
Nice to have you join us. Enjoy the forum.