Thanks Jan very much--this looks promising and I will try to test it out soon.
FYI I received this reply from one of the Ukelele development team members about the possibility of setting something up in Ukelele use Sanskrit-relevant diacritics in MS Word on the Ipad with Apple's smart keyboard:
"Sorry, but that's not possible. The iPad has a different keyboard
processing system to the Mac, so Mac keyboard layouts won't work with
iOS devices. As far as I know, you are limited to the keyboard layouts
available in the App Store. Keyman offers the widest variety, I think,
but developing a new keyboard is only possible with Keyman Developer,
which is Windows-only. But you might find what you need already out there."