Head Unitless Sound System

Been getting a build together for my 1970 Chevelle. The car currently has a mono AM radio set up. The catch is I want to retain the factory look and AM stereo so my plan is to do a hidden head unitless setup. Another requirement is that I do no want to run any additional wires into the engine bay thus limiting my amp power choice.

Speaker size and options
Front (stock is 6x10 center speaker)
Option 1 - Center speaker with 2 Audison APX5 (Audison Prima 1970-1972 Chevelle Dual Dash Mount Speaker)
Option 2 - Custom kick panels with Audison APX5 (Audison 1968-1972 Chevelle Speaker Kick Panels No A/C Pair)

I am open to other speakers for the kick panels but there is a space limitation of approximately 2.5" of depth.

I am leaning towards option 1 since it'll require less money and modification to the vehicle (I will lose some functionality of the factory blow through vents). Will I sacrifice alot of quality stepping down in speaker size?

Rear
6x9 mounted in the package tray - JL Audio C2 690TX

Again open to suggestions for the speaker. I am able to pick up those speakers from a friend for $100 USD.

Amplifier
Kicker 47KEY200.4 (Kicker 47KEY200.4 Compact 4-channel car amplifier with automatic tuning DSP — 50 watts RMS x 4 at Crutchfield Canada)

I really like the self tuning feature and the lower power consumption (I will wire directly to the fuse box to 20 amp cig. accessory).

Also was looking at Kenwood KAC M1824BT (Kenwood KAC-M1824BT Compact 4-channel amplifier with Bluetooth® connectivity — 45 watts RMS x 4 at Crutchfield Canada). Has integrated Bluetooth which is great but but lacks the ability to EQ (which I could potentially do off my phone to an extent).

Bluetooth
This JL audio MBX unit seems pretty common for these systems (JL Audio MBT-RX Marine-rated Bluetooth® adapter at Crutchfield)

One feature I would really like is a volume control on the bluetooth adapter. Does anyone know any units that are able to do that? Otherwise I can control volume from my phone (I just know one day it'll be full blast right when I start the car and cause a change a pants).

Another option is adding bluetooth/aux to my AM radio (AUX input jack for 67-72 AM radio - The 1947 - Present Chevrolet & GMC Truck Message Board Network). I am sceptical of how the quality will be.

Final thoughts, I am not looking for a crazy system, just something that will sound balanced and loud enough to hear over the exhaust system on the highway.

Any thoughts or ideas from those of you who have gone this route?