When they use lasers to analyze a piece of paper, they start at 400nm, blue, then go to 500, which they show as orange, but is actually green. They go to 600nm, which they show as green, but should be orange. This was likely done as the green/white contrast is likely more visible to the camera.
The lab should have already have the evidence from the receipt before calling in the detectives. The lab tech wasn't even sure that she had any info to give them until after the detectives arrived and she started analyzing the receipt with lasers.
At the end of the episode, Daniel is told that he is all the baby has, presumably meaning family as Annika is now deceased. However, Annika's sister was already introduced earlier in the episode, meaning that the baby also an also has an Aunt to care for her, though it is possible that Benson was lying to Daniel to ensure his cooperation.