I'd stick with a griddle, scramble in batches of about 20 at a time. It won't take much longer than the baking, will skip any guesswork (what happens if the baked eggs take 20 minutes longer or shorter than expected), and you can restock as needed, to avoid waste. Plus, eggs get pretty nasty after not too much time in a buffet line, no matter how they're cooked.
The sausages, fruit and pastry can be done in advance (and leftover sausages can be frozen). I'd have one person dedicated to each dish that needs to be cooked as you go (I'm not sure how you're doing the hash-browns or french toast), a kitchen gopher to fetch stuff, and two people dedicated to refilling dishes and keeping the buffet tidy, and telling the cooks what needs to be done next.