If your LM 365 has the KIB Multi-Plex Control Panel, the fuse is probably on the KIB control board. If your unit was built prior to October 2016, you may not have the KIB, in which case there could be an inline fuse, or perhaps a fuse in the main fuse box, or both.
The leads on pumps are usually only 6-8 inches. If you don't see an inline fuse on the old pump wires, don't worry about it.
For the accumulator, no idea.
For the Anderson Valve, if you want the pump to draw water from the fresh tank, you set the 4-way selector to NORMAL. In this position, a secondary channel inside the valve may allow city water to also flow to fixtures. If you leave the 4-way selector on CITY, you may still be able to have the pump draw water from the fresh tank by way of the secondary channel inside the valve.