All very good questions
As for the Butcher, you are character heavy and Curse from the Beasts lore will mess with any cav army!
The firebelly is useful, but generally in lower point games where his breath weapon will eat up entire units
... or against elves
Man Eaters are more versatile than MFC, but I prefer the MFC for the psychological threat over "Just a unit of tough ogres", the MFC will have your opponent re-think his deployments and play style on the go, trying to chaff them and keep them away from his core.
As for your Core, I tend to run 1 block of Ogres and 1 of Ironguts (smaller, about 8 strong like yours).
I would throw the bulls together with the SM and Bruiser, I would also try and fit a Crown of Command onto your SM in place of Fencers
If you need to you can challenge with your Bruiser, but the Stubborn will mean even a bad fight and you will be re-rolling on Ld8!
Then I would stick the Butcher with the IG's and go 3x3. If you stick a champion in the IG's then you can cast the likes of Panns and Horros on him from beasts giving him 6S9 attacks lol or T7...
The IG's will be used to clear tougher units and the Ogres will be your anvil! your MFC will aid your IG's, if you get a counter charge with those then that unit WILL die
You should take a wee look here - Tactica