The socket is what determines the cooler mounting arrangement so Kaveri which is for FM2+ won't require any different heatsink/fan than Richland. So if you decide to buy an aftermarket HSF for the Richland APU, it will fit Kaveri also. Any of the aftermarket HSFs list what socket the unit fits and generally it's all current socket designs.
Building a reliable PC involves more than just assembling the parts. You need to be able to configure all of the BIOS settings appropriately. This can be quite involved and frustrating as it can require a lot of trial and error with stress testing. It is however often the only means to get a 100% reliable PC.