I’m not pronouncing Adalind the same as Adelind and Adelinde. I pronounce the “Ade” the same way I would if it was in Adeline (Madeline with the “M” chopped off, just like you said), whereas Adalind looks like it should begin with the long “A” sound (like Ada Rosalind, which I love, by the way). So if you want the “Ada” pronunciation, then it’s no contest. Also, given Adelind’s similarity to the more popular Adeline, I feel like it looks much less “legitimate” than Adalind. And the extra “e” at the end of Adelinde doesn’t make it look any more complete to me. It looks unnecessary, if anything, unless you intend to pronounce the “e” the German way (add-uh-lind-uh).
In summary, while I really like the idea of Ada Rosalind, if you intend to call her Adalind, then I would definitely go with that. Adalind is a perfectly good name, and looks the most appealing spelled this way. I also think this way is the most likely to give you the “Ada” pronunciation.