I would not advise keeping different species of birds in the same setup. Whether they get along is hit or miss and even if they get along, they will still be their own separate groups. Guinea fowl in particular can be outright brutal to chickens. Obviously some people have success keeping them together but I still would not advise it. Not to mention different species have different needs. For example ducks ducks need deeper waterers than chickens (to wash their nares and dunk their food) and they tend to fling that water which can create problems for chickens as they don't like especially wet environments. Again, plenty of people do keep chickens and ducks together successfully (as Granny hatchet said though, don't keep drakes with chickens), depending on your setup it may create extra work and add complexity. It would be best for everyone involved if each species you want has their own space, that way if they don't get along for whatever reason it's no big deal. If knowing the risks you still want to try, I'd get a few duck hens. As long as you have plenty of room plus extra, the ability to keep things fairly dry and you make sure the ducks get adequate niacin they should be OK, individual temperments depending.