Invalid Queue element linkage is a problem in some of the best tested and most stable software in the kernel. In the absence of invasive Kernel extensions (you appear to have none) it is extremely likely to be a memory problem.
One issue that sometimes get glossed over is that MacBook Pro uses the processor chip's built-in memory controller, which is completely inflexible. This controller does not work properly with modules that are rated FASTER than spec. This is unusual, most computer Users are used to blithely installing faster models when available. But in these Macs, faster modules cause a pattern of crashes from a few times a week to a few times a day, with wildly different causes -- rather similar to what you are experiencing.
Three beeps is almost always a memory problem.