Oral Finasteride is strongly recommended. For oral Minoxidil, I have recently noticed that many doctors start to prescribe it, instead of the foam/solution forms. Finasteride works its magic on the crown but it needs time to kick in. Give it a year. It is not effective for hairline and temples. Majority of the surgeons will recommend to use it post surgery to enhance the outcome. DHI or any other pen is ok... its the surgeon choice. Some clinics claim that using DHI will make the transplant area heals faster. Again its all claims. Remember, DHI is a technique for implementation into the transplanted area... it has nothing to do with the extraction from donor, for which FUE is typically used nowadays. For me, I wouldn't pay more just for the DHI!
I'm not sure if Finasteride causes shedding but I'm certain that Minoxidil does.
For best results, I suggest you consider staying healthy, i.e., sleep well, workout, eat well balanced meals, drink water, take supplements (vitamins, omega 3, etc.). If you have dandruff, Nizoral should be your shampoo.