Obligatory "atheism is an answer to a question, nothing more".
1) Morality is illusory. There are no objective morals.
There are atheists who believe there are objective morals. I think Sam Harris is a person who talks about it. I don't follow his speeches but I remember someone mentioning it before. You can look him up.
Speaking for me, I don't believe objective morals exist due to lack of proof that they do. I fully admit that I might have a different view of what objective moral values could be.
There is no God to ground a spooky thing like mind-independent goodness under atheism.
Presuming God exists, you believe in subjective morality... subjective to that God. Objective moral values mean that God is also required to obey them. He does not. People of Abrahamic religions believe God is the source of all morals even when he kills children. This is subjective moral values.
Objective moral values is there is no entity that the moral values are based on. They are as objective as 2+2=4.
Therefore there is no objective good.
That's correct, as far as I'm concerned.
Atheists will assert that God wouldn't make morality objective either.
That's correct. This is because the usual bullshit I hear takes the following form:
My reply is that you, [theist], have no objective morality either.
God commands things because he is good, the very source and standard of goodness.
How about:
God commands things because he is evil, the very source and standard of evilness.
I can define things too!
relatively objective
I believe this is an oxymoron. Lack of objective morality means we have subjective morality. For instance, I believe X, Y, and Z. Am I right? Nobody knows. Do you agree with me? Yes? Cool. Do enough of us agree? Excellent, welcome to society. Will someone else in a few decades come along and say "what about Q and not X?" and if enough people believe it, that'll be the new morality.
For instance, let's examine Christians in the US and their views of gay people in the last 100 years. Clearly this has changed 180 since then and continues to gain more ground as time goes forward. What changed? The Bible? Divine revelation of a new truth? Nope, local culture changed its attitude and religious people found another verse in their holy book to justify an exact opposite moral position their ancestors held all while claiming to have objective moral values.
2) Free will is an illusion
I don't debate free will so I'm going to skip this one.
Everyone and everything will die eventually.
You sound depressed. I recommend medication or talking to someone. If you go to /r/aww and you think look at the worthless pictures of soon-to-be-dead life then you need to seek help. We find meaning ourselves. You don't need some dusty book telling you what meaning is. You can stop abdicating your responsibility for being an individual and think for yourself.
Your actions have no effect on your destiny
Can you sign a bunch of papers, pay for a plane ticket to a remote location outside of the US, and bring a gun? I'll prove you wrong but I can only do it once and you might not have enough time to realize that I'm right when your body hits the ground.
Atheists say that heaven would be meaningless too
Hmm, I don't say that. I think heaven would be horribly boring but I don't know about meaningless. I think you can find meaning in anything, even boredom. I've never heard of this argument before.
that's just a failure of imagination given the fact that God would be endlessly supplying novel experiences.
But what if I like playing first person shooters and that won't be available in heaven so there's at least that limitation - lack of electicity, console or computer, Internet, etc.
Acknowledge that everything is meaningless
I will say that this IS a common thing I hear from theists. You falsely believe that either God gives you meaning or there is no meaning. I don't know how many atheists are nihilists but I'm not one.