I haven't jumped into this case much because I cannot seem to catch up on the news from day to day! Things are moving so fast!
But having seen these types of searches so many times in missing children cases, I have to point out a few things:
It sounds to me as if they think the phones are in the house, and that might explain the x-rays looking for the shape of mechanical devices in the walls or floor.
As far as "new stuff" - that could mean that LE is looking for new clues, or that literally there is "new stuff" in the house. Not necessarily new, but building material new: replaced floor tile, paint, carpet. This could be stuff the family has had in the house all along, but suddenly they are doing home improvement. And while that might seem strange, I swear it seems to happen in every one of these cases - people redecorate while their child is missing. Is this evidence of guilt, or merely a bizarre way of coping? I can't ever decide. Stuff like that drives me crazy.
Unless they find the body, it could be months or (sadly) even years before we know exactly what they took out of the house and why they took it. So I wouldn't sit here expecting them to tell us much in an ongoing case.
I'm glad to hear they took dogs into the house, and also took some cushions out of the house. In the Madeleine McCann case in Portugal, they waited much longer to take in dogs, who hit a scent of the child behind the couch as if a body had been hidden there at one time, or perhaps the child had fallen there. But by the time they got a hit, the results were inconclusive. So in this case, let's hope they got better results.
In the Dunn case in Texas, some couches were moved out of the house immediately by the family and either given to a neighbor or hauled to the dump (can't remember - it's confusing), then the living room redecorated. One of the couches had been used as a bed by the child, Hailey Dunn, yet those were gone before the police had a chance to examine them! Then the police had to search the dump for cushions/pillows/whatever, and it's been downhill ever since. So I really think LE is doing a better job in this Irwin case.