The paint that Joe is using to paint the garage door when he speaks to the homeowner is an interior flat Benjamin Moore paint. If they were really trying to make it look good for prospective buyers, they would not be using an interior flat paint on an exterior garage door.
Scanlon tells Rob Walcott about Gavin Finch, "We know you murdered him, we just can't prove it". However, Allison saw the murder in her dream and also the murder weapon, namely a model of 414 Wright, the building that Walcott wants to blow up. That model would still have evidence of Finch's DNA and blood, not to mention Walcott's finger prints. A virtual smoking gun.