You need to plan to have outlets installed on the front side of the island. Outlets in the waterfall ruin the look, and outlets covered by the overhang don’t meet code. The easiest way to accomplish this is 3”
Fillers at each end of the island with an outlet in the filler.

That planning is done during the cabinet design phase. You can’t wait until the cabinets are sitting in the kitchen. You have no choice now but to cut holes in the waterfall to put them there. A 14” overhang will need more steel support than is in that picture too. Which also should have been designed into the cabinet layout. You should skip the waterfall and the overhang both unless the island is redesigned to have them.

The only way, short of bookmatching, the opposite unpictured waterfall end above can match the veining at the miter is if there is a seam running through the sink. Even jumbo engineered stone slabs stop at 131 1/2". On an island more than 59" long, pick where you want your seam that won't movement match please. Sink or miter.

While the estone manufacturers allow 3cm to cantilever up to 16" unsupported, in a run as long as pictured, it will sag. When it does, the outboard ends of your miters must self-destruct.

All of that cool stuff takes up space inside the cabinets. Unless the cabinets factored in that needed space from the beginning, none of it will work.

I assume the outlets can be run between the back of the cabinets and the wall facing the overhang

There is about 4-5 inches on the back of the cabinet. Between the back cabinet wall and the finish panel. I think I can fit the outlet there but than either take it up to the countertop popup or make a hole in the waterfall stone panel facing the oven (left).