I suggest that you get the True isolator wired to the second battery first and determine that it is getting charged up properly with the engine running. Then work with the stinger or whatever relay (which is typically used as an extension of the key-on accessory voltage from the Honda harness.) I want to see that relay coil get turned on with the key switch accessory circuit (from the primary battery). Then tie in your aux fuse block to get 12 volts from the second battery through the relay contacts when the key is on and engine running.
Then, I would move the power wires for the winch relay last, and wire the winch power directly to the terminal posts of the second battery. It is always a struggle getting all of the wires attached to the small battery terminals, you may decide to add auxiliary bus bars or terminals to avoid a clutter of wires mounting on the battery posts of the second battery.
I like to wire each of these things a step at a time and test it. Or, you can wire up the whole circuit and then it is much more difficult to fix if it does not work as expected.
Good luck, I am planning to do the same with my 500 soon.