The website says that we need to fill and then they will provide a letter to be sent to the school asking for the transcripts.

It says that we need to provide the copies of the certificates and the school needs send them the transcripts directly in a sealed package.

Can you share your experience, what you did and how it went? How does it work if the school no longer exists

Try ICAS CANADA
web: icascanada.ca/fsw (assuming you are applying for "federal skilled worker")
tel: 5197637282

on their website they say current time is 8-12weeks. Good luck

That's where I got the details that I mentioned in the OP. I was looking for input from some who has gone through it already.

I sent my documents to WES.org/ca and it is in process of evaluation. For Transcripts from TU I had official sealed transcript from TU which I included in my packet. and I included my copies of diploma from US univ. I asked for official transcript with the univ here and they send my offi transcript to Wes.org/ca. I am waiting for my final evaluation.
I think it should not be any problem if you have official sealed transcript from Nepal.
For school no longer existing I don't know if you're talking abt Nepal or here in US. I have no idea.