All of your assumptions are correct. Circuits don't get any simpler than the ones for this system, as nearly all components wire directly to one of the two controllers. Inputs are sinking (ground is switched), and outputs are sourcing.

The roll bar switch is wired to sockets 3 and 4 of the soft top controller's "Y" connector -- it's the longest one of the three on the controller. The soft top controller operates the hydraulic pump through a relay located at the pump assembly in the bottom of the trunk. The signal comes from socket 7 of the "X" connector.