Loss of erections and libido does set in pretty quickly when you start HRT. Of course your doctor will have the final word, but if he is happy with your blood tests then you should be alright.
It sounds like you may be your doctors only transsexual patient. As long as he is fine with your process he should be pretty well prepared for assisting you in your second puberty. There are no real gotcha's as long as your liver functions remain stable. If he has any questions, he can consult with other endocrinologists who have worked with transsexual patients. If he needs some names, I'm sure myself and others on the list can make some suggestions.
You can be orgasmic after SRS, but you will have to learn to cope with a womans naturally lower libido in comparison to a male. My surgeon, Dr. McGinn, was quite specific in explaining that SRS was not a cure for a reduced sex drive. And she recommended that her patients should attempt sexual gratification as often as possible prior to surgery, because the surgery itself removes between 80-90% of the sensate tissue in the glans to create the neo-clitoris. Following surgery it will take some time to retrain your brain to acclimate to the new arrangement and become orgasmic again. Also having vaginal orgasms can happen as well but you will have to practice that also. The sensations of your G-spot are conveyed over a different set of nerves, the pudendal nerves, and they are not affected by the surgery at all.
You should be fine, just don't obsess over it.
If you think about it, it is sort of funny to say that you HAVE to masturbate (or whatever) prior to surgery as one of your pre-surgical tasks. My mother would have been scandalized.

-Sandy