My theory on the hits in the backyard are this...
CA took the clothing and hosed them off. Possibly by or in the sandbox area.
Water from hosing off the clothing "pooled" at the pool area.
Rinsed clothing was then carried and draped in the playhouse to drip most or all of the water out before she took the clothes into the house to put in the washing machine.
The water might dilute the cadaver scent slightly, but only slightly and won't eliminate it.
Strongest scents would be where she rinsed the clothing, where the rinsed material "pooled" and where the clothes dripped dry in the playhouse area.
Dogs would indeed "hit" on those areas and track the trail to those areas.
If the clothing was dry or almost dry when she took them into the house, there may not be much for the dogs to track into the home.
I would be curious to know if those same dogs were worked around the washing machine/laundry room. Pause for thought.
Also, something to keep in mind. Bodies which are donated to science often are used for "cadaver work" for the dogs. While the bits and pieces here or there are useful and very beneficial, full human body decomp has thrown some dogs due to the intensity of the odor. They will hit on the outskirts, where the minimal odor that they trained on (pieces) is, often nowhere close to the actual body. Dogs need to be proofed and certified on full cadaver to help minimize incidents of this.
Hope that helps some.
If the Anthony's said "Good Morning" to me passing on the street I'd have to run home and go to bed because surely it would be night time.