i would have put the chicks under her at night in her nest where she was brooding not move her she would have maybe accepted them in her own nest as having hatched overnight rather than being but under her in a new area, you might give it another try in her old nest whereshe is setting . good luck
i usually keep my just hatched chicks and hen in a small pen inside the big coop for a week to ten days then let them loose into the big coop, mama will usually keep them safe from the others and take them out to free range when they are ready
she should set for another 1 to 2 days so if any are going to hatch they will, you can candle an see if the others are close, as long as the other chick has food and water , you are doing everything right just set back watch and enjoy, chicken math has begun lol
when you candled was there an air cell at the bigger end of the egg and how big was it, if it was a solid dark egg it could be rotten and could explode. was there any peeping when you lighty tap on shell with finger?
i have never had any luck with chicks that old and after the hen has moved off the hatching nest she will more than likely kill the strange chicks especially if they cannot get away from her. usually 2 to 3 day olds can be put under the hen while she is still in the egg hatching mode.
i agree i think blondie is a roo based upon the three rows of peas coming on its comb also it has some rusty colors on its wings. you really have some pretty birds there good luck hope only the one is a roo.