Hello all!
To kick things off, I'm completely new to WFB.
I've decided my first army will be Dwarfs and I bought the Dwarf army book and the 8th ed Rulebook.
I've read the Dwarf tactica and got a pretty decent grasp on how to build the army, but I have a few questions regarding the actual model kits and boxes as well a question about warmachines.

1) Was thinking about getting 2 Battallion boxes to kick things off, and would like to know if the stuff in the boxes are the same as you'd get if you bought them separately. I see the Dwarf warriors in the Warrior box have a musician with a drum and the ones from the bat box have horns. Also the bat box description doesn't specify if you get a command group for each of the 2 warrior groups of 16 or just one for all 32.
2) I was also going to grab 2-3 boxes of Miners and was wondering if the Steam Drill is something that you could have one of the dwarfs holding or if it is a tripod-style extra. I never see any of the miners in any of the photos actually holding one. Also, do the miner boxes have the same pony and wagon sprue that the BfSP has? Lastly on the miners, where can I get those awesome looking miners from the back of the dwarf army book?!?! The miner boxes at my lgs and the GDW site look just like the warriors and thunderers.
3) When you put an engineer on a warmachine, does it add a 4th figure and/or an additional wound to the warmachine, or does one of the 3 crew become the engineer. The crews of all the dwarf warmachines certainly look like one of the models could be an engineer, but I'm not sure. I must have overlooked it in the rules.
4) Lastly, in addition to the 2 bat boxes and miners I plan to grab a few metal lords, a runesmith and the BSB which will leave me with about a hundred bucks left if I want to be able to actually paint, base and add some terrain to my army. Would this overflow be better spent on a pair of Stone Throwers or a 3rd bat box? (I intend to add more later, but this is what I've got for the near future. )

Thanks in advance for any advice/info you guys have for me!