In terms of the look/function, if the build goes the way of a 6x6 Hybrid E-Cruiser then it seems the third (Tesla) axle should be a lift axle. This is desirable because it allows the rig to be just a regular LC200 on-demand, and Tesla-pushed on-demand.
So, again, if you have two hundred miles of flat road, you can go off the 4x4, and drop the rear Tesla axle, and just coast on electric power. Then, when necessary, lift the axle and go back to 4x4 gas. Then, when necessary have a 6x6 rig, such as on uneven terrain or when pulling a trailer off road.
Here are a few photos to show that, though out of the “mainstream,” the “tag axle”/“lift axle” have a long and varied history in off-road and ultra-heavy load use. All images are used under educational “fair use” rationale — not for commercial use / strictly not for profit.