You seem to be using two SPI devices. Are they both using the same SPI settings, and unique slave select pins? If they aren't using the same settings, do you know that both libraries configure the SPI correctly before each operation?
Also, the the purposes of testing the RAM and display and compatibility between them I would use a test sketch that did the minimum necessary to show that each device worked, and leave out all the complexity of your real application - that's probably irrelevant, but we can't know that for sure until you eliminate it.