What's one more goat?

So I am building a 40x70 pen is a right now semi wet spot due to the unreasonable amount of rain from last year and this spring but it normally is dry as I used to have a garden there. This will be my pen for my goats I am getting Nigerian dwarfs I had wanted goats for milk and simply because goats and I already have money down on 2 doelings and decided to go for a great looking buckling as well. Now I have the summer to construct him another pen somewhere before he starts his breeding and I figured I need a whether to go with him as well for a roommate. So non registered whethers in my area are going for about 150$ as he doesn't need to be ADGA but the rest of my herd will be. Now I was contacted by someone that actually had 2 doelings left already 8 weeks and 5 bucklings to whether and offered a price of 200 for the doe and a whether along with her, he offered this to the entire goat site but messaged me PM right after as im located close by and had talked to him before about getting one off him. I was planning on 2 does 1 buck and 1 whether but this is a very limited offer and what is one more doe right?
Only problem is I have to put on post in yet and the supports then stretch the woven wire fence and build the hut and the rain has all but stopped my progress this week. These two are all ready to go he might hold them a little bit for me but if not I was going to put them in a 10x10 dog kennel in the yard until the pen is ready.
So what amount of hay would I be looking at per goat I seen some people say 1 bale a week for 5 that isn't bad at all and what size hut or shelter should I build?

Hi Hunter;  I'm a pig person not a goat person but I have been around quite a few goats. So for what its worth here's my 2 cents worth.
The deal you are being offered sounds like a good one.  Like you say whats one more goat?
About your pen and the current wet weather...  well if it were me, I would don my rain gear and muck boots and go to work. Yeah working in a slicker in the rain is no fun but... IT BEATS sitting in an office pushing computer buttons all day... :) Besides when you work on a farm , you work in all weather and all hours of the day and night. Wait till your birthing at 2AM...

As far as their shelter size. I would say that depends on you.  If you are planning on milking and birthing then you want a real building with enough room for both.  
If you are talking a shelter to hang out in,  then it can just be a roof with 3 walls. I build mine at a 90 degree corner of the pasture.

How much will they eat ? If they are like other livestock. If you give them too much they will trash half of it.
Buy a few bales and see how long it lasts.  

REMEMBER goats will try to eat anything and they can climb almost as good as a cat... Your buck may be able to reach those does with ease.