Hi, welcome to the group! I'm not sure that there's anyone here who has quaker experience. What I've always heard about them is that they're nippy lol. My experience with them is very limited - I fed some pizza crust to one at a bird club meeting several years ago and we both enjoyed it.
The internet reports that they're one of the "big personality" birds, who are lively and fun but are also noisy and destructive, and can be aggressive to humans and smaller birds. It's probably not a good idea to let the quaker mingle with the cockatiels without close supervision because the tiels could be at risk. She will probably LIKE a noisy household because it's exciting, but in the beginning you should probably find a relatively quiet spot for her so she can get used to it gradually.
The amount of attention you give to the quaker in the beginning should be the amount that you expect to give on an ongoing basis, because if you pay a lot of attention to the bird in the beginning and then cut back it will cause problems. In general it's fairly easy to make friends with a handfed baby by holding some food in your hand for it to eat. Handfed babies associate human hands with food anyway, and may chew on your fingers if you don't provide something else for them to chew on. The usual rules for a new bird apply - it will learn to trust you if you act trustworthy. Do things that the bird likes so it wants to spend time with you, and avoid startling it or doing things that it doesn't like as much as possible.
This looks like a fairly good article on quaker personality:
http://www.birdchannel.com/bird-magazin ... ieves.aspxI haven't looked at this one in detail, but here's an online quaker handbook:
http://quakerhandbook.com/