It is confusing. Answers to a couple of your questions:
TVS explanation, from a layman to a layman: The TVS (transient voltage suppressor) is meant to deal with voltage spikes which are too brief to trip a circuit breaker, but may be severe enough to damage electronic components. These spikes can happen whenever there is arcing, such as during derailments. The way they work is counterintuitive--you install them with one end connected to common and the other connected to power. This looks like it would cause a short circuit, but it doesn't. The TVS is "open" (not connected inside), until a high-voltage voltage spike occurs. Then it closes and creates a short circuit. This sounds bad, but what the short circuit does is prevent the spike from reaching your engine's electronics. Instead, it attacks your layout wiring and transformer. But the wiring and transformer are pretty tough, and the spike is very brief, so no harm is done. You do not reset a TVS. They reset themselves. You would want one on each circuit, and the closer you can get them to the electronics, the better. Between the clips on the lockon is good. Inside the engine itself (if you know what you're doing) is even better.
The main purpose of a circuit breaker is to protect your wiring from a situation where too much current is flowing through it (like in a short circuit condition). Because the same derailments that cause voltage spikes often cause short circuits, too, a fast breaker can help protect the locomotive by limiting the number of those voltage spikes (open circuit = no voltage = no voltage spikes). But a TVS can, in principle, prevent any voltage spikes from ever reaching the locomotive's electronics at all.
Like Adriatic said, engines without any electronics do not need a TVS to protect them.
Electrically, all track types are the same. The only difference is the ones with individual wood or plastic ties do not have the two outer rails tied together from the factory. Fastrack and tubular both do.
The way you described the Transformer/Power House > PowerMaster > Layout + Cab > Command Base setup is correct.
A Track Power Controller (abbreviated TPC - there are two models, TPC300 and TPC400) is a newer version of a PowerMaster. The TPCs are supposed to be better, but on the layout at my parents' we use a PowerMaster; it must be 20 years old, and it does the job fine.
Aaaaand one more wrinkle: you mentioned operating switches with the remote. You can buy Fastrack switches that are wired for TMCC/Legacy. If you use other switches, you will need an accessory controller. Basically, you send a command to the controller, and the controller lets the current through to operate the switch motor. But I have never used these, so unfortunately, I can't give you any specifics.
Hope that helps some!
