The E field AMP connects to controller with MINIMUM CAT cable (5, 5e, 6) and connects to the PREAMP with coax. You want less cat cable, so the E Amp should literally mount with a 1' CAT to the 2 input on controller. The Coax is an integral part of the LP filtering for the current design. The E PREAMP would have to mount vertically in an enclosure, with the probe directly connected, extending vertically. Future development may incorporate a single E/H combo amplifier stage in some fashion, however, using experience gained from the present 'dual system' operation. Should that be implemented, I'd expect both E and H to operate on some similar "preamp" concept, so each can be located in its own separate space.
There might be some possibility of EMI from a nearby H field amplifier. I noted some during a test with the two (E PREAMP and H AMP) close together. (Board to Board induced, not from antennas/probe). I would have low confidence in both AMPLIFIERS or PREAMP next to each other without some fancy metal box, and that could negatively affect both amplifiers. E field Probe wants Air under it, not metal
Also since you're limiting the H antennas and E probe to the same location, height, etc,... this would preclude locating each in its own separate quieter, more 'sensitive' environment. A good H field environment may not be the best E field location ! (and vice versa).
My E field Probe and Preamp are ±22' in the air, on a mast mount, 100' coax to E AMP, which is 1' CAT6 to controller.
My H field Ferrites, Amp, is 40' north, in a "sweet spot" that is about 2m Cubic, (because of my very noisy M environment) with the AMP directly to the antennas, on 50' CAT6 to the controller. That's its only sweet spot, and mounting the E field in the same location was completely out of the question since that location is inside, 4' above the garage floor. E field needs to be OUTSIDE and in the air 3-4 meters.
Mike