Hey Calab, I know they have some hybrid cable actuated hydraulic body brakes for bikes that might work for you. I have heard they work well for fast scooters. I think the advantages of full hydraulic brakes, if you can do it, are overwhelming. I bought a ebike front brake with two calipers, for two 203mm discs. Since my hub motors already had one disc, I thought it would not be too hard to adapt another and have two discs for the front. After feeling how fast, and heavy, the bike became with the second motor I knew even two bike 203mm discs would never satisfy me. I am absolutely in love with how well these brakes work brother. The weight of the motorcycle caliper is not much more than the two bike calipers I was going to use. The 3mm thick motorcycle disc is pretty heavy and the big lever is a little heavier than the bike lever. My estimate is it adds about 2lbs. extra. To me they are worth every penny and every microgram, and as you astutely noted the pads should last forever! And they sound so cool, very silent.
I am also loving the 26”x 3” tires. They fit 26” rims, but they are 27.5” diameter. I had to hog out my rear frame, and then reinforce the tubes cut, just to get them to fit in the back. They have at least twice the cushioning of the stock tires. Even with no suspension, on average roads it feels like riding on clouds. Highly recommended for those that can use them. I would like to see how the real 4” fat bike tires feel and act.