A lot going on in that post!!
The signs of the day of judgement are just that; some signs of what may happen. Some are from the Quran, some from Hadith, some from weak Hadith, some from ppl of knowledge. We can't know exactly of course, because these are things from the future and unseen.
From what I understand knowledge and Quran being forgotten will happen to Muslims as well. There will be Muslims who say "la ilaha illallah" but won't know what it means and will just say their ancestors used to say it. But there will still be a group of good Muslims until the end. Not sure what you mean by "will they suffer".
These are all different signs and we still have to go through the Gog and Magog, the Dajjal(anti-christ) and the second coming of Jesus. The last major sign we know will be the sun rising from the West. And then of course on the "Last Day" Angel Israfil will blow the horn and everyone alive will die, and he will blow it again and everyone will rise up for the Day of Judgement.
The 'some ppl of the Ummah' quote I'll assume is talking about Muslims.
No Muslim is perfect sister!! We are all struggling! As for your sins, if you repent for them following the conditions inshaAllah you will be forgiven and enter Jannah.
I wrote an article once long ago about the Journey of the Soul that talks about some of these things. It was checked by a Shaikh so you can read it here inshaAllah: http://jannah.org/articles/souljourn.html