A thought that I had after rewatching TGG:

If Moriarty organisate crimes, why should he contact Sherlock to solve them? Wouldn't this really bad for his business if he reveal his own customers?

So that is my theory:

The wife actually killed her husband or gave a killing contract to get the live insurance and the brother killed Connie Prince to get her house how John said (with the cat). And maybe it wasn't the aim to kill the old blind woman but to collaps the building for some reason.

Moriarty left false traces because he knew that Sherlock expected a genius case and not a simple domestic murder (like the case in Minsk) and Sherlock solved it in the way Moriarty wanted. Wouldn't this the best way for Moriarty to promote himself? At least he used a detective consultant to perform his own crimes.