Well when styg started the project, the native resolution was 1024*768, but of course the standard changed over the years. I play at 1600*900 at home and when I test some stuff, sometimes at 1920*1080 but quite rare. I know that the font can be quite small, once we have time for it, we will put a larger font in Underrail. Icons will stay at the same size, to much work to redo all, we are to occupied with other stuff.
I scribbled me some map of the new areas today, well even for us it gets hard, and we have maps on paper. So maps will be implemented. So, yes. When? I don't know, later perhaps. In the upcoming update for sure not, we are busy with content at the moment.
Once the new update is out I'll show you my ad-hoc maps :p with special coffee splatters texture !
There are no cheats in the game, but you can go and check the wiki, i think Epeli did a fine job and made screenshots of every area. That would serve your purpose.