So, firstly, three replies... thank you! Its going to take me some time to research and fully understand the replies. I'll try to give some of the comments/questions.
Q1a.
Q1b.
A1. Honestly, I don't know. I've heard that a capacitor b/w power & ground will stabilize your 12v source, but, now that I apply that logic to my schematic, it's clearly not b/w power and ground. I'm going to investigate this, but clearly it seems I've made a mistake.
Q2.
A2. Can I still use this transistor to step up the current to my light or is there a better one out there for my PWM purpose?
Q3.
A3. Okay, so don't be mad, my schematic was wrong, it's actually D9 that I was connecting to 
Q4.
A4. I'm having trouble following what it means to have an open collector output and what the implications are. I can research this, though, thanks.