I don't believe that you will need biological samples in able for the spell to work.
The only thing that's been needed are your names and birthdates together and if Ashra will be the one who will cast your spell yes sometimes she is asking for your pictures, even separate pictures.
I don't believe that any biological samples will be needed because in the first place, your lover don't know that you are casting a spell for them so it's very difficult to steal any biological samples.
I also think that sometimes, the spell which needed the biological samples like blood, hair or something else is the black magic spell, but with the white magic spell your names, birthdates or even pictures will be enough for your spell to work.
You don't need to do anything just the spell to work, and you don't need to steal any biological samples.