If she intends to throw her daughter under the bus, her defense team will have to convince a judge there's enough evidence to charge HH. I think that's impossible. I don't think any states allow a person's defense to be pointing a random finger at someone else and then calling witnesses against that person.
There would have to be compelling evidence that HH did it. I can't think of any. If LS thinks she knows that HH did it (!) then LS will have to take the stand (and be demolished). Since HH can be called to the stand by either side, that would certainly happen (the prosecution would call HH and HH would have alibis and give no evidence that she killed Gannon, in fact, one would presume that HH would totally flip on LS if LS tried this).
Since LS is lying and is the only person with "knowledge" about Eguardo, Quincy or HH being criminals - she has to testify to that. There is no other evidence. No blood on HH's shoes - blood on LS's shoes instead. So far, no DNA of Quincy or Eguardo involved. By now, they've probably accounted for the various DNA in the house by testing AS as well (and Quincy and Eguardo).
If Eguardo is the one who came and repaired the carpet, he may in fact testify as to what actually happened to that carpet (LS is lying about it, IMO).
No defense is allowed to name 3 random people instead of the defendant, although they can try and sneak it into the closing argument, there would be no evidence presented - unless from the beginning, the judge allows it.
It could get really interesting if the defense even try to hint at Quincy, just as an example. Not only would Quincy then be called to testify, but it would open the door to Letecia's own lovely past, which I believe includes at least a brief stint as a sex worker.
But the real star witness is sure to be Albert Stauch himself, to testify about all the various things Letecia said and when she said them. Quincy's name doesn't come up until February! Letecia lies to AS consistently and continues to do so. He knows what's missing from the house. He knows where that bed was supposed to be that morning. He also knows LS and how she's behaved in the past.
So do not worry. She can't claim that HH did it, it's absolutely crazy to do so and there is no evidence and it would only cause HH to testify against her in more detail than she might otherwise.
Because HH will definitely be called to the stand. Once the DA establishes the overall timeline, then HH will testify about her run to Dollar General to get trash bags, etc. I'm sure HH will also be asked about what parts of the house were cleaned (and they will all correspond with where Gannon's blood was found).
HH is slowly getting over the shock of the actual events, but by the time of the trial, her main concern is going to be keeping herself out of jail and telling the truth. Her own attorney (one she'll have to pay for, herself, so hopefully she can do that) will advise her to tell the truth.
I think once in court, HH will in fact tell the truth. She may try to cover up some things, but the jury will readily see that - she's so young and court is very intimidating.