Regarding your minoxidil allergy, most likely you are sensitive to propylene glycol which is a common solvent for minoxidil solutions. There are solutions that are devoid of this. However, based on the photo provided, you would be a good candidate for restoration as your hair loss pattern is somewhat slowly progressing and stable. You have wavy hair which covers more than straight hair and gives a fuller appearance, and donor region should be adequate if you have not had prior procedures. Minoxidil allows any hair to grow thicker and longer but would not be "necessary" for a transplant, your dominant donor hairs grow regardless. However, for future planning, the scalp hair you currently have could miniaturize over time requiring a second procedure to reinforce without preventative meds.