Initially I like your idea... and maybe in fact myself will make it on that way.

however ONCE I got a short from blue line ( I didn't know about my car electric on those days yet ), when the alt brush isolator got broken and all the blue line began to heat up to ign switch, melting slightly a couple of plugs, so thinking on that, is not a bad idea get it fuse protected like painless sugestion.

The fuse for the dimmer line.... mmmm I don't think is EXCESIVELLY necesary and splice tan and orange together will work. Is already protected by the pink input line. Just that if some short at dimmer circuit, will blow at the same time with parking lights. A smaller fuse on dimmer circuit will blow the dimmer fuse first keeping safe the parking circuit.

Now... what circuit is more important to keep it fused ? which one is easier to get a short ?... make your choice

I think on this, is about a personal preference for each one