There’s not going to be a ready to go biped because Epic doesn’t use Max. They use Maya. All the stuff you get with UE4 is from their actual projects. The bones don’t correspond to the biped in Max. The proportions are different ect. They might, and I really mean might, be persuaded to create a workaround (or maybe someone else will) but I think they might be a little more concerned about other areas of the engine’s development. In any case the bones I get when I export from UE4 are real bones (meaning that’s what bones look like in 99% of the 3D programs out there) and I use Blender. The bones you get when you create a biped in Max are actually the oddballs of the industry. All of that having been said you should be able to export the animations and re-target them in Max though it will likely require a bit of clean up work. Otherwise why not just go ahead and create your animations? You just drag your project out by waiting.