The Core Services consist of the networks running throughout the body that are necessary for supplying nutrients, energy and communication, and waste-removal.
In other words, the blood supply, peripheral nervous system, and lymphatic system, plus electrical power for the parts that need it.
The general idea is to continue the theme of biological components being enclosed in non-biological protective materials by having flexible pipes that contain up to four different channels, two for liquids: Blood and Lymph, and two for wiring: electrical power and electronic or optical communication signals.
It might make sense to separate these two kinds of channel, as the electrical/optical channels have different requirements to the fluid ones, and will be attached to non-biological as well as biological components, so may need different routing.
What are the requirements?
Electrical power will be needed for some parts of the body, particularly the neural interfaces, computing, and sensory systems.
Power storage, backup storage will be the main challenges. Distribution can be via simple wires.
Rechargeable batteries, fuel cells, supercapacitors and piezoelectric generators all seem feasible. Multiple redundancy will be essential, as power failure would mean total loss of sensation, motor control and communication.
What Exists Now?
What can be done right now?
What needs doing now?
Speculations, suggestions, criticisms, etc.