Position of particle emitter relocation and particle opacity in Particle World

Hi everyone,

I am not familiar with After Effects and need to create animated snow flakes using custom snowflakes. I was able to figure out so far to use Particle World and animate my particles to fall down. So far so good.

I am having very hard time adjusting the flakes to maintain same opacity from birth to death. No matter what I do they are always fading in and out. Is there a way to stop that? A way for them to stay at 100 opacity from start to finish?

I am also trying to move the particle emitter above the composition window so that it appears the flakes are falling down from above it. Currently they just appear from a random places of the stage. I have attempted to select the snowflake image with the particle effect and move it up, however I am not able to select anything. There is no binding box (my apology I am not familiar with the proper terminology); but I refer to the box with tiny squares that appears around the composition window when a solid, or an object is selected.

Is there a way to move the particle emitter?

Thank you so much!