Using a timer that regularly read the file for what colour mode is in use I solved the question.
Here is the script that reads and calls the changes:
" Set colour scheme (and more) to light mode
" Set colour scheme (and more) to dark mode
This was the color schemes defined in paper color theme.
Just pasting this in the vimrc worked!
let g:terminal_ansi_colors = [
\'#eeeeee', '#af0000', '#008700', '#5f8700',
\'#0087af', '#878787', '#005f87', '#444444',
\'#bcbcbc', '#d70000', '#d70087', '#8700af',
\'#d75f00', '#d75f00', '#005faf', '#005f87' ]
So "peachpuff" has just the white background in console. You can patch the source directly, or add this to your vimrc:
augroup peachpuff | au!
autocmd colorscheme peachpuff hi Normal ctermfg=0 ctermbg=223
Still not exactly the same as in GUI, but it's much closer now.
P.S. Or you can "extend" an existing color scheme ...
I was able to set these elements to different colors by targeting these two highlight groups:
So in my case, I added the following to my .vimrc, mirroring the way the colors are established within the distilled colorscheme's files:
hi clear EndOfBuffer
hi clear NonText
hi EndOfBuffer ctermbg=0 ctermfg=8 cterm=NONE guibg=NONE guifg=#...