Often we are so preoccupied with who is Muslims and what they are doing and what they are not doing. Rather we should look at what we are doing ourselves in our personal life.
Just like how Rasullah(saws) handled somebody who said when is the hour? He replied, what have you prepared for it? So instead of being preoccupied by who is this and who is that, look at how far is our own imaan. As often these questions don't really have that much benefit in even knowing the answer to it.
I will stand on my own on the Day of Judgement. Besides that, currently no unity really exists among Muslims. The day that we without any hesitation finally can clear the Ummah is when the promised one arrives. When will he arrive? Allah knows. It could be in our lifetime or even in 1000 years. So right now, we don't need to focus who are Muslim and who are not. Look at ourselves if we are Muslims and we practice Islam as how we should practice it.