Installing New Stereo System, 2017 Honda HR-V, 2013 Mazda 3

*Just realized I forgot to put a ? In the subject / topic. My bad*

I came across this forum just randomly browsing just wanted to say looks like a cool place and you guys look like you know your stuff. Glad to be a member here.

So I'm installing a system in a 2017 honda hrv lx. In about 1 month I'll be putting it in my other vehicle a 2013 Mazda 3.(not the model with bose system)

Equipment:
-4 Gauge AWG power/ground (CCA)
-Speaker wire, RCA cables (OFC)& Remote wire
-Stock head unit in hrv -_-
-Alpine S A32F 4 channel
-Alpine S A60M mono
-Polk 12' DB1242DBC DB+ (I love the sound of this sub. I have hooked it to a boss mono and it sounded good lol)
-4 JBL GTO 629
-4 Channel LOC
-Inline fuse & Distribution block

My questions are:

*Can I jump my remote wire to all 3 components? 1 wire to 2 Amps & LOC? Also I know it doesn't take much for an amp to turn on but I have a couple add-a-circuits should I use ignition fuse from box or is the "blue wire" on back of this crappy stock head unit adequate?

*When I've done a system before I have ran power and ground on right side and Speakers & remote & other on the left but I notice that Speaker wire always crosses the power and grounds path. Is there a way to run the cables so they don't met at all?

*I heard that you can't ground to same ground point so I never have. I have seen others say they ground to negative on battery terminal?? Can you?? Wouldn't your ground be like atleast 3 or 4 feet long? In this car I'm ground to the manufactures 2 rear ground points. I believe for brake lights & whatever else needs grounding in the back. With the equipment is this a good place to ground? (I have shaved the ground hole, bolt to bare metal)

*Finally in your opinion do you think I need a capacitor for this car it really does not have a lot of power and I may be over stressing but I feel like if I excellerated the music would get louder hahaha that's just how this car feels lol

Thank you for taking the time to read my bull. I appreciate it

I wouldn't try to power on all three components with the remote out of the stock head unit. I have never had an issue with newer products and running wires right beside each other. Personally I prefer to have everything grounded at the same point to avoid ground loops. You can ground back to the battery if you want, like in a boat or some newer aluminum body vehicles. I don't care for standard capacitors, if I need it, go for a super capacitor. Just an opinion , I know you didn't ask but scrap the CCA go get some OFC for power and ground.

I know trust I didn't even wanna buy CCA nut OFC is just so expensive right now. All wire where i'am went up. But fo sho when I can I'm going to buy better wire. Also I prefer you give your honest opinion lol

So for the remote should I run 2 or 3? If I use the add-a-circuit instead of the HU could I put them all on ignition fuse?

I thought ground loop was when they were all in one ground? I could be mistaken though that's why I'm here lol