I would prefer Delphi as a nn for
Delphine or
Delphinia, but I can see it standing on its own. Brings
Dulcie to mind, which I prefer over
Dulcinea. I do like the floral pairings you made, nice feel to those. The other feeling I'm getting is virtue names. Assuming you are pronouncing Delphi, with an "ee" sound at the end:
Delphi
BlossomDelphi
LilacDelphi
JuniperDelphi
RosabelDelphi Plum
Delphi
PrudenceDelphi
ConstanceDelphi
HonorDelphi
PatienceDelphi True