Need an electrical engineer within the uk to customise a hifi with a raspberry pi

I have a Denon M39DAB hifi/stereo CD player and I want to do the following:

1. add raspberry pi 3 b+ and divert some power from the hifi supply to the raspberry pi
2. Make a hdmi cutout on the case of the hifi in line with the other ports and either mount the hdmi port from the pi up against the case directly or use a cable to extend
3. Connect audio from the aux out of the pi to the aux in or the hifi, internally.
4. Install lineageos https://konstakang.com/devices/rpi3/LineageOS17.1/
5. Create something like a custom boot loader / login / fake service screen that says:
DENON ENGINEERS MENU, Enter code to continue (that will only proceed to boot Lineageos when the correct code is entered)
6. Install a microphone within the remote control of the hifi, that can be used as a microphone with the pi on any communication apps for phone calls
7. Ensure Bluetooth headset works for video/phone calls on android app (ie WhatsApp)

Optional:
1. Install secondary OS (OSMC) and create a button combo on the remote control that will switch between LineageOS and OSMC
2. Make a cut out in the case, and install a camera, also for use with WhatsApp on android.