Apparently I don't know how to post images. My link points to Nelson's LDR buffer.
You mentioned that you will be using LDR with no active parts. I hope you know the sever requirements of LDR.
You mentioned that you would replace pot with resistors if you use B1 buffer. Don't replace pot. Remove it.
I couldn't find any input impedance of your current amps nor your upgrade amps. If you post those, other people here can help with buffers to feed 7 amps.
You mentioned that you will be using LDR with no active parts. I hope you know the sever requirements of LDR.
You mentioned that you would replace pot with resistors if you use B1 buffer. Don't replace pot. Remove it.
I couldn't find any input impedance of your current amps nor your upgrade amps. If you post those, other people here can help with buffers to feed 7 amps.