Yes, Just place them in the appropriate Glyph Boxes so you don’t have to go to all the problems of mapping new glyphs
Perhaps start with How to add characters defined in the Supplementary Planes... to learn about Supplementary Planes
Take a look into fonts like Ariel or Times New Roman that already have these glyphs.
Also, overlapping glyphs - #3 by Bhikkhu_Pesala
Do a search for diacritical mark and you will find many others.
Good Luck!