I have a lot of experience building 18F micros into laboratory test machines, some working for the last 22years.
Include in that:- 16F & PIC32MM. I have a Raspberry Pi and am familiar with using it.
If I understand you correctly, it is only the PIC18F work that you require?
You will handle the Raspberry Pi side of it is that so? (I would obviously use the RPi here for in-house testing)
The PIC18F schematic is given by you, will I be building the hardware here, or just the firmware?
The PIC18F47K40 is a 5.5v part (not 3.3v).
Once I have answers to these, etc., I'll be able to offer a firmer proposal.
rgds, John