Windows' clip seems to be very picky and will accept non-Latin input only encoded as UTF-16LE as noted here. Even pwd | clip in cmd.exe doesn't produce meaningful contents on pasting.
I found utf8clip which didn't work in my test VM, but might work for you. If it does, you can modify mappings like this:
" Yank current directory path to Windows clipboard with forward slashes
nnoremap yp :!pwd %i | utf8clip<cr>
" Yank path to current file to Windows clipboard with backslashes
nnoremap yf :.!utf8clip %i %Pl<cr>
" Yank path to current file to Windows clipboard with forward slashes (needs sed)
" nnoremap yf :.!sed '!\!/!' %i %Pl | utf8clip<cr>
You'll need to make utf8clip available somewhere in %PATH% (could be in $VIFM/scripts, which is added to %PATH% implicitly) or specify full path to it.
A third variant would be to find a converter from UTF-8 to UTF-16LE and use it in combination with %Pl macro. Macros like %d in echo %d seem to turn non-Latin characters to question marks as well, maybe echo does that, which is why %Pl is used.