Are these new grown hairs on my scalp's top part or they are miniaturized/vellus hair? (Photos)

There is initial shedding with Minoxidil. It will take up to 6 months to see results. I suggest seeing a hair loss expert now to go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone which can help with hair regrowth and/or hair transplantation. See an expert. Best, Dr. Emer

It's too early to tell. That said it does appear that you have a higher proportion of short hairs than expected - this certainly could be a sign of therapy working but it's too early too say. The same phenomenon can be seen in a telogen effluvium. You seem to have a mix of vellus hairs, terminal hairs, newly regrowing hairs and miniaturized hairs. Please see a physician for follow up and monitoring.

The photos can't determine if you are having benefits from minoxidil, but you eye can tell you if there is more hair there