I LOVE Deborah. As most everyone knows, I love everything Norma Shearer, and Norma Shearer has a granddaughter named Deborah (her sisters are Shoshana and Elana), so, of course, I love it, too. :)
Devorah/Dvorah/Devora/Dvora would all be pronounced the same: 'dev-OR-ah'. The 'e' in my pronunciation is said rather quickly, there's no lingering like there is on Deborah (because the stress isn't on the first syllable).
I really don't know which I prefer. I do love both Deborah and Dvorah equally, though I do go through moods in which I slightly prefer one over the other.
A modern sibset of Deborah and Judith would strike me as odd, but in a very good way. :) I would be absolutely overjoyed and thrilled if I came across a real life sibset that included Deborah and Judith. They sound so refreshing nowadays, so I totally advocate their usage.