Eric, may I suggest that the following characters could be added to
the Pali fonts? Though the PTS has standardised on the M with dot
below (as I have too), some still prefer the M with dot above.

I am not a Sanskrit scholar, but I believe that R dot below macron is
also useful. In my fonts I compose these from R dot below plus macron
to ensure a perfect match to R dot below.

uni1E40 Latin Capital Letter M with dot above
uni1E41 Latin Lowercase Letter m with dot above

uni1E5C Latin Capital Letter R with dot below and macron
uni1E5D Latin Lowercase Letter r with dot below and macron

In my own Unicode Pali fonts, I have added 20 symbols like white
circle, black circle, half circles for moon days; Yin Yang, Dhamma
Wheel, and a few other Misc symbols. I add exactly the same characters
to all four styles of all fonts as symobls do not require bold or
italic versions, nor different typeface designs.

You would be welcome to copy the symbols from my Unicode fonts if you
think they may be useful: http://www.aimwell.org/Fonts/fonts.html