Well, birding is all about reach and fast lenses, so I would go with the 7D, 300mm and the 1.4 and leave the rest at home. You can use the 5D3 with the 70-200 for the wild turkeys and have the 2.0x in reserve just in case you need backup for the 7D. I've seen some phenomenal shots from Halls Road taken with the 7D, so even if it is not as good as the 5D3, it still has the ability to put more pixels on the subject.
Unless the wind is blowing swirling snow I would not worry about changing lenses.