Once again, I have already answered this. My mind is not set up on anything, nor am I stating my point of view, understanding or belief. To me it is very simple.
1- If ISA AS has died, according to the Holy Quran, then fine, so be it. No one can come in his As place; there is absolutely no concept of Re-incarnation in the Holy Quran. Mirza can not be second coming of ISA AS, nobody can be.
2- IF ISA AS was taken alive to the heavens by the Angels on the Commands of Allah SWT, then only he can come back. Mirza or any other impostor is still out, no room for them.
Tell me what part of my arguments you do not understand? For us Muslims this is not as a big issue as you made it out.
Its very simple from our point of view as well. We as Muslims believe that there is NO concept of reincarnation in Islam. We as Muslims also believe that every human being taste death, weather it be an ordinary person or Allah's sent Prophets. There is no exception to death.
Regarding your first point : It is not very hard to understand really.. when Jews were waiting for Elijah (AS) to appear before Jesus (AS), Jesus (AS) referred to John the Baptist as being the Elijah (AS). This is clear that a name or title can be given to someone , provided he is just like one of them. To put it very simply, Jesus AS was to Moses as the new title holder of Jesus will be to Muhammad. Only condition now is, no new religion can there be now. Islam is what it is, and will remain till the day of judgment.
regarding your second point : ok, now since re-incarnation is not a belief in Islam.. the only way you can justify your position is if He (AS) himself appears ? You know very well that death do not accompany the livings. Once dead, He is never to return in His bodily shape. This is exactly what we are talking about here. There is no mention of Him going to heavens bodily and coming back of him bodily.
PS: As for your whole paragraph, there is only one thing i wanna say. Yes, prophet did get killed, and yes there have been prophets where Allah has helped them. I wanna know what is the case with Jesus (AS) according to Quran. We know Jews could NOT kill him, that is out of the question now. Then what happened to him ? Was he exalted to heavens? if he was, then Jews plan of killing Jesus succeeded in their eyes ( they have killed look alike of Jesus , and hence according to them they have killed him ), but no, Allah says..they planned, and we plan, and we are the best of planners. Now, if he wasnt killed, nor went to heavens..what exactly happen to him? Can i then safely say He survived the crucifixion ?
PS2 : also a very interesting thing to look in to is his duration of crucifixion. Please do let me know if this topic interests you. Please do look into it yourself.