N400 interview de-scheduled saying "because unforeseen situation"....TEN months already since i filed the application.

Sorry to hear. They are really slow.

Do I need an immigration attorney

You are unlikely to her a filing fee refund. Sorry.

Sibling green cards take a long time.

This is regarding completing masters in 3 semesters

I would submit the transcripts and try to get as many transfer credits as possible.

Internet news article as a corroborating evidence in asylum case before

Safest is always hardcopy. But doesn't hurt to have other formats too, if the impact is greater.

As a permanent resident can I bring in my fiancée from another country to marry me here in the US?

Coming to US on tourist visa, then getting married immediately is inadvisable. A K-1 fiancée visa is preferred, but is available only to citizens...

Do I have to provide a statement in N400 explaining why I did not register for selective service?

Suggest you provide a truthful explanation.

Hi, I am currently on H4 visa and I have filed for H1B through my company.

Uscis is notoriously slow. Suggest you talk to company attorney.

Duration of Stay

If you had a normal program end, then you have a sixty day grace period from program end date.

What do i have to do if i traveled from USA for long period

You may want to consult a tax advisor about your situation