Is it true that after a FUE HT person will have "doll like" hair? How many hairs does 100 grafts provide?

You should not be able to detect a good hair transplant surgery.  A bad hair transplant surgery may look like "dolls hair".

if done properly with current techniques a hair transplant should never look like "doll's hair". It depends how much area you need to cover but 100-200 grafts is a very small amount.Our average case is 1800 grafts.I recommend an evaluation with an experienced Hair Restoration surgeon to determine your needs.

it is not true ... I advice you have a FUE; you would get the desired hairline in just one sesssion of dense packing hair transplant.During the placement of follicular units there will be a mixture of single, double and a few triple grafts, which help to create the soft look of a natural hairline. For the first few lines always go for single grafts, later doubles Triples and others.So that a smooth transition will be there giving undetectable hair transplants.