Changing rapidly from finasteride to minoxidil or viceversa will mantain the hair conserved due to the first treatment?

The white stuff at the end of the hair is most likely a waxy substance produced by an oil gland. This is normal.  It does not mean you are losing hair.

For all of us who have never met you, it would be impossible to say if a photo can tell if your hair has receded.It would also be impossible to tell if your hair loss will "get worse" without an examination.Maybe you always had a high forehead or maybe you have a receding hair line.If you want a...

Generic finasteride 1mg should have the same ingredient as brand name Propecia. The difference is the name.If you believe your medication is counterfeit, then followup with your doctor.  There is no way to tell from a photo.

You paid money to go to a hair clinic but doubt their treatment recommendation?If your hair loss is due to low iron levels, then it would be logical to correct the problem.If you are not sure and want a second opinion it is best to see a doctor for an examination.Otherwise it would be just guess...

A scalp biopsy cannot tell you what your treatment should be. Generally a doctor would need to examine you and also understand your goals.  Scalp biopsy basically says you have a non-scarring type of hair loss which is very non-specific.

You probably will not find the answers you're looking for on the Internet (a medical diagnosis for your condition).  What you describe is a complex case mixed in with pregancy.  It is best you seek another doctor for a second opinion if you are still having issues.