This is an under-tree layout intended for play by and with kids, right?
No way I'd go without the TMCC Lock-On for its fast breaker.
I'd also plug it all into a Tripp Lite Isobar, or similar metal-housing surge protector.
Then again,
I'd also wire in a slow breaker like from Scott's Odds-n-Ends. (Or, does the DCS gear have this in it?)
I'd also upgrade the house panel with an Arc Fault Breaker for the train's circuit.
And a SurgeBreaker (assuming it's a QO panel)
Maybe all this is a bit much, but... you're not just protecting the trains - you're protecting the kids.