Who cares what breed it is as long as the egg color is what you desire? You're after a blue egg, right? Just get a bunch of hens and see what they lay. Breed birds from blue eggs or whatever.... or go buy blue hatching eggs.
I like Welsummers too. They are beautiful chickens and lay a beautiful egg. I also Like Ameraucanas/EEs -- you can get them in almost any color and they lay some big colorful eggs too! If I were keeping just one breed, it'd prob be Welsummers.
I don't think you need to worry about...
If I were building a permanent coop, I would keep the dirt floor. Wooden floors are expensive and require more care than a dirt floor. Just make sure coop and run are big enough and it'll be fine.
I like Welsummers. Nice birds, nice roosters. Pretty too. BCM roosters look pretty nice too, though I hear they can be mean.
I have started some BCMs, so don't have much expereince with them...None with Barnevelders.
Once the chick starts 'drooping' and bleeding, you've got only a little time left. Fortunately, Sulmet works pretty quickly. I never knew Corid was safer, but in my experience Sulmet really works and will turn a chick around in a hurry if it's coccidia...Never used Corid.
Yes. It won't be protected from raptors, but should do fine. I wouldn't worry too much about the the 8ft coop. You could just make it one side of a pentagon. Those kennels don't have to be rectangles. :-)
http://catawbacoops.com/
I like these a lot. You can use it for a breeding pen, or a broody coop, or a coop for up to 6 birds. Easy and cheap enough to build. I am going to build a half-length version and use it for a broody coop.
My Ameraucana/EE lay very well and other than egg shell color, I can't tell any difference in the eggs. Relative to the size of the bird though, the eggs are pretty large.
http://petchickensofvirginia.com/group/forums/viewtopic.php?f=9&t=2889
Sturdy, strong, yet light enough to move around. Chickens get grass every day. Adequate shelter from the weather (sun, rain, snow, wind). Predator proof! I'd recommend this design: