WinSCP already has this excellent feature to edit multiple files at one prompt with edit dialog
https://winscp.net/eng/docs/task_edit
You can also open an existing file this way, or even multiple files by separating their paths with semicolon (;).
But trouble is that input size of that window is limited to just 256 symbols.
This could be hardly enough for some very long full name of the file at remote side, not to mention multiple pathes of files.
I would recommend to increase it at least to 32/64K or something.
Sometime there is a need to open multiple files using full path for each.
Thank you for your great work!