I'm in a similar situation (rejoining the hobby after 35 years with zero knowledge of DCC) and will give you my two cents based on my last year wrestling with similar questions.

Circuit breakers: if you have them, use them.  They are intended to prevent more serious damage elsewhere (decoders, etc.).  I use PSX (PSX-AR for reversing routes), and they made my wiring much simpler to understand, and saved me from what could have been expensive repairs as I learned my DCC wiring.  Plus they reset themselves.

Blocks: I think less is more.  I originally had about 10 for my 12x15, but after getting help in this forum I cut it to six, plus two reversing blocks (wye and loop).  I split my main yard into two blocks (north and south) with a third for the reverse loop, and then at logical break points along the main (I have three switchbacks so they are each one block).

I have the NCE, but not wireless, and am loving it so far.  I'll let others comment on your power requirements but from what you've said they sound about right from what I've read.