p4v does not show the complete list of checked out files

I don't know if it is possible in p4v. In a command line shell however you could use

p4 opened -c default > list_of_files

and examine the list with your favorite viewer.

To mass change filetypes from the command line you can use:

p4 edit -t text <filepattern>

or

p4 -x list_of_file_to_change edit -t text

To change all files of the default change list to filetype text you would use (UNIX/Linux)

p4 opened -c default | sed 's/#.*//' | p4 -x - reopen -t text