The digraphs are actually read as dialogue in the DTE, (I remember il is "e ", so Vile Shell reads as "Ve e Sheth" or something similar in Windhex32.) but for menu-related strings they read as their special tiles. So if you have any blank space at all in the font block, it's free for item symbols to add in.
Edit - il, li, and ll should be 8A, 8B, and 8C. 8D should be free. If my knowledge of the ROM is right, 8D to BF should be free, then CA to EF, and F0 and F6. That should be ample space for all the icons you need.