Except this exact solution was proposed in the first hearing and was flatly rejected as contra to policy. They were open to 'creative solutions' but returning the children to the same address was explicitly stated as being disallowed.
The testimony seems more ambiguous than that. They (specifically Sweep) doesn't specifically use the word "address."
(The transcript is
here.)
This appears to be the section you're talking about, and out of context it seems pretty unambiguous.

"The -- the foster home cannot -- the licensed foster home cannot be the home that of which the children were removed from."
"And what impact does the licensing issue have on placement?"
"It would mean that the home could not be licensed. Therefore, the people residing in that home would not be able to get licensed, and the children could not be placed with them."
Now, the meaning of "home" is fairly broad. A "home" does not have to be a "house" and not every "house" is a "home." However, "residing in that home" and "were removed from" seem to imply a physical location, not some vague idea of a "home."
But this is in the redirect of Sweep after this testimony just immediately prior to the quoted sections above:

When asked specifically about the scenario of the grandparents moving into the house where the Rekietas were living and Nick and Kayla moving somewhere else, Sweep didn't just immediately reject the idea and say that's impossible because it's prohibited by law, but instead said they'd need a plan to do such a thing, and when pressed further, said she'd have to consult further with the agency.
So while it looks cut and dried just looking at the first testimony I quoted, earlier on we had testimony from the same person that suggests the real obstacle is the lack of a plan for doing it safely. And in an earlier hearing, the issue was that they hadn't been allowed to inspect the home thoroughly to ensure that the dangers, i.e. drugs, had actually been removed, and Nick acting shifty about allowing access to the bedroom.
tl;dr
- Nick and Kayla proposed the grandparents moving in to the house the children were removed from while they moved out
- Nick and Kayla subsequently indeed changed their address
- Sweep said KCHHS wanted a plan if Nick and Kayla's proposal were to be accepted
- Sweep later said that the children can't be fostered in a "home" that they had been "removed from"
Hence, while I'm not saying this has actually happened, I don't think it's "impossible." That's a pretty strong word from what we know.
Unlikely, perhaps.
I follow Rekieta very closely, and know him somewhat well (as much as you can from online only contact), and the thought of the 9 year old on coke never crossed my mind.
I was absolutely shocked, aghast and enraged at that news, and I already had an exceedingly dim opinion of Nick and his character at the time.