your actual tongue weight will be way more than that fictional dry number.
you're correct in that it doesn't include the things you mentioned. that number is for a stripped-down, no-options trailer.
go with the 600/6000lbs., it'll work fine.
you'll definitely need a WDH and the Equalizer is the best one for the price, in my humble opinion.
be sure to check RVW's price, comes with free shipping.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC