I was pretty sure RnRc was the first LIM launch coaster? But even if I'm wrong they wouldn't exist without the people mover.
The following coasters existed before RnRC that used linear induction or linear synchronous systems:
Tower of Terror II - Dreamworld (Australia)
Superman: Escape from Krypton - Six Flags Magic Mountain
Flight of Fear - Kings Island and Kings Dominion
Batman and Robin: The Chiller - Six Flags Great Adventure
Linear Gale - Tokyo Dome City (Japan)
Mr. Freeze Reverse Blast - Six Flags Over Texas and Six Flags St. Louis
Mad Cobra - Suzuka Circuit (Japan)
Volcano, The Blast Coaster - Kings Dominion
Joker's Jinx - Six Flags America
Poltergeist - Six Flags Fiesta Texas
RnRC was hardly an original design. It was an off-the-shelf design from Vekoma that has since been used for two additional coasters. All Disney did was enclose it and tack on a theme. And Linear motor technology was not invented by Disney. The concept can be traced back to the 1840s, if not earlier.
The ToT elevator was used as an example for LPS ride vehicles, I think they are pretty reliable! My guess would be CA didn't have the space for a horizontal shaft so they designed it without it.
No. The horizontal shaft proved incredibly problematic and was cut from all subsequent designs. Plus the arrangement of three shafts with 6 load areas increased hourly capacity.