Ermygerd time to write another block of test. I had some time to kill so here's my analysis:
Okay so first of all Bronzong is great and all, but its UU for a reason, is debateably outclassed in OU andsince you have a blissey I'm going to have to agree with JarJar and say Skarmory will win in this case. So i'd replace Bronzong with:
Skarmory @ Leftovers
EVs: 224 HP / 252 Def / 32 SpD
Quite a classic Skarmory set, but still extremely effective. It can tank any physical attack, roost gives it recovery, spikes is its choice of entry hazards and Whirlwind and does some phazing for those foolish setup attacks like Dragonite who try to take advantage of Skarmory's setting up.
Brave Bird is to stop being complete taunt fodder and does decent damage added with STAB. Roost also helps mitigate the recoil damage.
So Blissey is awesome =) but my moveset change would do this:
Blissey @ Leftovers
Ability: Natural Cure
EVs: 4 HP / 252 Def / 252 SpD
Yup stealth rock on Blissey. Stealth rocks is probably the best entry hazard so we need it - and with Skarmory's spikes most of the grounded pokemon take alot of entry damage. Softboiled is for healing and Toxic is to cause some damage while Flamethrower is used to hit the steel types who can't be toxiced (However this set is still killed by heatran). You can run Thunder Wave to give team sweepers a better chance of getting through however. The EVs are to give Blissey some chance of surviving physical attacks and its ridiculous health is good enough with minimum investment. With Skarmory, Blissey makes a great synergy .
I'm going to skip Crawdaunt for now and go to Breloom. I'd make a minor change so here;
Breloom @ Life Orb
EVs: 4 HP / 252 Atk / 252 Spe
-Seed Bomb/Bullet Seed
Spore and Swords Dance to mess aounrd and setup. Seed Bomb and Mach Punch give STAB and Mach Punch gets a technician boost and priority. Bullet Seed is also an option over Seed Bomb to have a chance of breaking Sub. and also the Technician boost but has some luck base.
Magnezone I'd use as a steel type trapper. So;
Magnezone @ Air Balloon
Ability: Magnet Pull
EVs: 4 HP / 252 SpA / 252 Spe
So this guy traps steel types and kills them with HP fire. Substitute gives it a little advantage after the Steel type is killed and full speed/sp attack helps it do more damage. Air Balloon is to survive ground attacks until hit by a different type of attack. Because Magnezone traps and kills steel types you can change Blissey's set to softboiled/toxic/icebeam or seismic toss/stealth rocks since steel types are delt with and no longer and stop toxic
Now to Crawdaunt. I personally wouldn't use it and would replace it with something like Gyarados so;
Gyarados @ Life Orb/Lum Berry
EVs: 252 Atk / 4 Def / 252 Spe
Dragon dance is self explanatory, Waterfall gives STAB, ice fang hits dragon types. Taunt is to shut down walls and can help get up more Dragon Dances to attempt a sweep. Moxie is pure awesome and Life Orb makes Gyarados even stronger, though Lum Berry is a choice simply to absorb a status effect on the switch or something like Static.
For the last pokemon Jirachi is awesome so;
Jirachi @ Life Orb/Leftovers
Ability: Serene Grace
-HP Fire/HP Ground
Pure calm mind sweeper and completely deadly after one or two boosts. Psychic or Psyshock depedns, as Psyshock hits through special walls, while Psychic hits harder on a more regular basis. Similarly the Hidden Power is pure preference and depends on what your team needs to counter more. Leftovers can be used for more survivablity over Life Orb, but life orb's extra power can be invaluable
Welp I'm done what a block of text! Hope I helped and GL