My first question is can PIR motion sensors be placed in any other pins besides PWMs?
Pusle Width Modulation, PWM, is a form of digital output (a square wave to be exact). For a basic PIR sensor I don't see why that would be required, all I'm familiar with just need a digital input.
If not, what is the biggest board that has the most PWMs? I am working with about 8 White color LED Strips and each one is independent to other strip.
I'm answering this because what you want to do with the LED strips might require PWM pins (or software PWM but I beginners should have a working understanding of hardware PWM before trying that). It would be good to determine whether or not these strips have built-in control logic for things like dimming or patterns (some strips have it and some don't). If they are just strings of LEDs, you will need to use PWM to dim them.
is the largest board in physical size and pin count, and it has more PWM enabled pins than the most Arduino boards (15). However, it is significantly more expensive than an Uno or Leonardo
(which have 6 and 7 PWM pins respectively).
Also the one PIR sensor is particular is to power all the LEDs at a dimmed level, while each LED has their individual PIR to power them at full brightness. Thanks for answering my rookie questions.
This part shouldn't be a problem, you'll just need to have the proper conditional statements to control the LEDs based on what mode the device is in.