Hi,
In answer to your question can you eat their eggs..YES they are really nice, two eggs are about the same as having one chicken egg. I had 3 guineas and recently one died due to our family dog

this one that I lost I think just died of shock as she had been sitting for almost a month on eggs, I was lucky to have a clucky chicken whom was given some eggs and she hatched 8, with one dying not long after hatching. it is 5 weeks on and I have a lovely bunch of seven keets, in which will just become part of my mixed family. My teo adult guineas share housing with my 12 ducks, they get along just fine with all...I am yet to introduce my keets, but I will when they are a bit bigger and have had time with their foster mum whom takes them out on expeditions! They have a complete hut and a large fenced off yard for their free roaming, whilst all my other chickens, ducks and guineas are in a large fenced off paddock. they all go to their huts each night and are locked away safely and then let out to free range in the day. My male Guinea at the moment is enjoying roosting high up in a tree that is within my paddock and over looks their hut and the chickens hut, he comes down each morning when I let the ducks and his female companion out.
I suppose if you have your guineas confined and not free roaming they might use nesting boxes, but from my little experience they tend to make their nests in an area that they think is safe....My female at on 30m plus eggs the first time and she created a nest in a secluded area of the paddock, as I said we have a complete paddock that is fenced with six foot fencing all around, so she was relatively safe, nothing eventuated from those first batch of eggs, we built a small frame with a roof on it and placed it over her, so as she was protected from rain, heat etc. I live in Australia and we can have 4 seasons in one day!
The second time she collected just as many eggs and once again not in her hut where there are nesting boxes, she made yet another nest out in the paddock, so once again we built a roof over her...As I said I lost her sadly, but now have seven keets and they are doing well, once they are older, I will integrate them to my paddock and fingers crossed things go smoothly. I have a plan on how I will do this and I am sure it will work out.
All I can say is yes eat the eggs, and yes they should get along fine with your chickens, they tend to hang with their own and just wander around, as for what Guinea Goonie says, I agree, chickens can be the worst offenders of bossing their own around...I suppose that is why they have their pecking order and call it a pecking order!
Good luck with your newbies, I just loveeeee guineas..........