Checking into the medications is a wise thing to do. Your hair loss pattern could progress further without them. If you get a hair transplant without meds the doctor should plan ahead in case you do lose more. You want a hair transplant that will still look natural if this happens, you may need a second hair transplant which will depend on donor availability.
If you have an in person consult or see the doctor on the day of surgery, they should check your hair for signs of miniturisation and advise you accordingly.
Looking at your pictures I would guess between 2500 - 3000 grafts is what you need to create a new hairline and fill in the thinning areas. Graft numbers will all depend on what you want to achieve and what the doctor advises.