Easiest bosses I'd say are the King Black Dragon and Giant Mole (so annoying without the elite falador shield)
Um, for the King Black Dragon, for mid level combatters, I'd suggest this sort of set up
Full Slayer Helmet (if you have a black dragon task)/Bandos Helmet/Helm of Neitiznot
Saradomin's Whisper/Amulet of Fury/Amulet of Glory
Bandos Chestplate
Bandos Tassets
Ganodermic Gloves
Ganodermic Boots
Sixth Age Circuit/TokKul-Zo/Warrior
Kiln Cape/Fire Cape/Skillcapes
Drygores/Chaotic Maul <---- if you have super anti fire
The inventory shouldn't really matter I guess, just try and mix and match to your personal preference
Fun bosses to duo and trio with would be any boss in GWD, perhaps even Kalphite King if you are with 2 other experienced combatters
and yes, Fight Kiln is easy and you can do them with your stats. No food needed if done correctly, a shield would help a lot unless you have Guthix's Blessing