Introducing pullets

Hi,

I am about to adopt two pullets into my flock of three. They said they are Ameraucanas but I think they might be EEs (you guys will have to tell me when I post some pics.)
I have three EE pullets about 2 months old. The two I am getting are a week or two older.

I have been reading about introducing new birds, but I wanted to get yall's opinion.

I have been free ranging my three for a few hours a day while I built them a run, which is now nearly done. The adopted birds will have a small coop that can fit in the run. I plan to put their new girls' coop in the run and keep it closed, while letting my girls run outside. This way they can see each other and get used to it.

It's kind of a hassle to keep them all separate, so I'd like to get them integrated as soon as I can. However, they are also pets to my two youngins so I want to avoid violence as much as is practical. How long is sufficient to get them used to the sight of each other and let them mingle? I was hoping for a week or less.

When I put them together, how long before I can feel like it was a success? If I watch them for a few days and they seem okay together is that likely the case?

Thanks Chicken People!