Mazda5 6MT - new to me. Intro and a few questions

[Fuzzel]

Hi all,
Picked up a 2012 Mazda5, 6MT 2 weeks ago for $2500. 155k miles. Pretty much rust free (I'm in the PNW).
Has a few bumps and bruises and was an insurance write off. Runs and drives nice, not even suspension work needed. Lovely!
Went through Inspection on Monday and it's on the road now. (had a 2006 5spd Mazda5 a few years back, generally familiar with the concept of the car).

About to do fluids, spark plugs, a few trim pieces today.
Already collecting some mods and parts info.

Working on figuring out ...

• The steering is annoyingly light (in ALL situations). Pretty much zero resistance. Is this normal?
  The PS pump was replaced by previous owner, possibly related to the pass. side accident it had, leading to the insurance write off.
  Replacement has JY writings on it. Is there an adjustment or sensor to tweak?
• I'd love to add the OEM hatch spoiler. Some holes would need to be drilled. Are hatches generally prepped underneath the outer metal to accept a spoiler?
  (reinforcements, extra holes, whatnot)
• Brake pedal feeling is subjective but are these usually pretty squishy on the CW gen.? Prev. owner changes pads but they feel like I should try to bleed them.
• My butt HATES the driver seat. The reinforced seam-lines )or whatever lies beneath) on the bottom are super annoying. I read Mazdaspeed3 seats / cushions can be swapped in. Are there any other good choices? I wasn't able to find much.
  Has anyone tried to put a Planted(TM) base for a Mazda3 in and then raise an afterwmarked chair, mounted on top?
• Fog lights: I'll check today if these are pre-wired. Looks like I need a stalk; is that just plug and play? If not pre-wired, what do I have to do?
• I want to take out the rear seat bench and build a deck that can be extended forward. Either with hinges that can fold partitions forward when taking out the 2nd row chairs, or can be added in a modular fashion per 2nd row seat. Ideally I wand a pretty much even floor w/o chairs but lower (and not haul those seats everywhere I go).
• A bit more noise from the engine would be nice, either via intake or exhaust or both.
• Shopping for a front bottom splash pan and sides...

Cheers & TIA for any hints, tips and welcomes!