No.Does WinSCP compare the remote and local file-size after download?
Does WinSCP delete original remote file without download confirmation?
Does WinSCP still delete without confirmation?
I do not understand how does this differ to the previous question.
How does WinSCP process the successful download validation?
I'm not sure what you mean. Are you asking how WinSCP checks if the transfer was successful? It largely depends on the protocol you are using. But in general, if the transfer completes without any errors, it is considered successful.
I am afraid that it would delete without properly downloading files as someone mentioned in other forum article long ago.
No it won't. And I believe it never did.