According to the older than dirt gentleman down the road here in the way back of central texas.......
They get the same humidity, same temps. Body temps in birds are the same ...even tropical birds... around 99 degrees farenheit.
Reptiles and platypus and other "weirdo" critters are the ones that get different temps... (you gotta love the way old folks put things sometimes lol)
You can take an ostrich egg, keep it at 99F, and just wait for awhile, and you're fine.
humidity seems to be 4-60 % for each species, too...waterfowl at the higher end, others at the lower end...but all can be incubated together.
Of course, I wouldn't be rolling quail eggs with emu eggs... that could be very messy...especially if the emu hatched first.
I hope this helps!