I could be wrong, but (there are MANY SRAM aficionados who will chime in, now, to verify/refute the following) ...
YES for the cassette.
NO for the derailleurs ... because, it is my understanding that (as with most of SRAM's MTB shifters/derailleurs) the pull rate of the cable(s) is different ... that is, SRAM "stuff" is mostly proprietary -- justanotherreason why I wouldn't buy them!
It's a small consolation, but you MIGHT be able to use a non-SRAM front derailleur with their shifters, but MY understanding is that SRAM's front shifter doesn't even allow for trimming with their front derailleur, so that is something else to be aware of (that is, I presume SRAM compensates for a crippled mechanism by having a wider separation between cage plates ... that, presumably, means that the shifting may be incrementally/insignificantly slower).