I just did this exact combo this weekend. Engo 10k on Rubicon X JKU with Maximus 3 winch plate for 10A bumper.
First off, you do NOT need a vacuum relocation bracket. It fits with about 1/8 inch space between the engo winch and that poorly located vacuum bracket.
What does not fit is the wires for the solenoid box on top of the engo winch. The wires normally can be routed through the grill, but in the case seating it down in the bumper, the wires run into the bottom part of the grill. It pushes hard on the grill. I might have been able to force it, but in chose a different route. I bought a few longer 6foot wires and relocated the solenoid box to the engine compartment next to the battery. I am very happy with how it turned out. The winch is almost hidden in the bumper now.
I want to stress that this poor fit of the engo solenoid box with the 10a bumper and maximus plate has nothing to do with the quality of the maximus product. I am 100% satisfied with the maximus winch plate. It is solid, and I would buy it again. The problem is with the wire cluster f#\< coming out of the back of the engo solenoid and where it just happens to line up on the jeep grill.