Yes, they would still be considered atheist even if they believed in some weird spiritual or religious shit. An atheist is simply someone who lacks belief in a god. Nothing more, nothing less.
Edit: Oh look! There's an atheist here trying to change the definition of atheist and using the No True Scotsman fallacy. How ironic.
Atheism is the belief that there is no God. So any religion that has a god is not atheist. There could be an interesting debate on Buddhism. Gothama Siddartha (the Buddha) never claimed to be a God and he constantly told his followers to check what he was saying and if it didn't work throw it away.
Its really a gray area of discussion..
A true Atheist do not believe in an afterlife or spiritual being or the supernatural.
Others make some allowances.. so it's really up to the individual atheist.
Buddhism has two forms, one is atheistic and the other is not (at least as I understand it.) The same holds true for Satanism and possible a few other religions. While atheists tend to be more skeptical and thus generally do not believe in or see the use of religions or other superstitious practices, this is a side effect and not a central tenet of atheism. Atheism is simply the lack of belief in all gods. So, if a religion does not express a belief in a god or gods, then it could be considered atheistic.
Jainism Im not sure of. But Buddha refrained from using the term God because he knew that unenlightened people misunderstood the term, especially during a time period when the majority of the population could not read or write.
The Buddha avoided the typical religious practices and saw that many of them did not lead people to God. This is not to say that he did not believe in a higher power. Although the Buddha did not mention a god in his teachings, he still attained the awareness that Krsna and Jesus and taught the same spiritual truths.
If you don't believe in gods, you're an atheist. Also I believe the definition of Religion involves some kind of supernatural deity (God), so Buddhism for example isn't really a religion if they don't believe or worship a God, it's more of a personal enlightenment, philosophical type of thing. Some people may just label it as being spiritual or one with nature. Some people try to claim that atheism itself is a religion, because they think it is solely about belief and leave the supernatural/God part out of the definition.